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88-457: AOS/VS exploited the 8- ring protection architecture of the Eclipse MV hardware with ring 7 being the least privileged and ring 0 being the most privileged. The AOS/VS kernel ran in ring 0 and used ring-1 addresses for data structures related to virtual address translations. Ring 2 was unused and reserved for future use by the kernel. The Agent, which performed much of the system call validation for

176-448: A Trojan horse , spy gadgets that look like normal devices but turn out to be something else, such as a USB Keylogger. These devices actually are connected to the device as memory units but are capable of recording each stroke made on the keyboard. Some spyware authors infect a system through security holes in the Web browser or in other software. When the user navigates to a Web page controlled by

264-422: A web browser other than Internet Explorer , such as Mozilla Firefox or Google Chrome . Though no browser is completely safe, Internet Explorer was once at a greater risk for spyware infection due to its large user base as well as vulnerabilities such as ActiveX but these three major browsers are now close to equivalent when it comes to security. Some ISPs —particularly colleges and universities—have taken

352-517: A computer administrator that runs everything under limited user privileges, when a program requires administrative privileges, a User Account Control pop-up will prompt the user to allow or deny the action. This improves on the design used by previous versions of Windows. Spyware is also known as tracking software. As the spyware threat has evolved, a number of techniques have emerged to counteract it. These include programs designed to remove or block spyware, as well as various user practices which reduce

440-498: A different approach to blocking spyware: they use their network firewalls and web proxies to block access to Web sites known to install spyware. On March 31, 2005, Cornell University 's Information Technology department released a report detailing the behavior of one particular piece of proxy-based spyware, Marketscore , and the steps the university took to intercept it. Many other educational institutions have taken similar steps. Individual users can also install firewalls from

528-432: A guest operating system to run Ring 0 operations natively without affecting other guests or the host OS. Before hardware-assisted virtualization , guest operating systems ran under ring 1. Any attempt that requires a higher privilege level to perform (ring 0) will produce an interrupt and then be handled using software; this is called "Trap and Emulate". To assist virtualization and reduce overhead caused by

616-467: A hierarchy of modes exists (ring-based security), faults and exceptions at one privilege level may destabilize only the higher-numbered privilege levels. Thus, a fault in Ring 0 (the kernel mode with the highest privilege) will crash the entire system, but a fault in Ring 2 will only affect Rings 3 and beyond and Ring 2 itself, at most. Transitions between modes are at the discretion of the executing thread when

704-526: A large number of rogue (fake) anti-spyware programs, and widely distributed Web banner ads can warn users that their computers have been infected with spyware, directing them to purchase programs which do not actually remove spyware—or else, may add more spyware of their own. The recent proliferation of fake or spoofed antivirus products that bill themselves as antispyware can be troublesome. Users may receive popups prompting them to install them to protect their computer, when it will in fact add spyware. It

792-465: A legal framework governing the use of such software. In the US, the term " policeware " has been used for similar purposes. Use of the term "spyware" has eventually declined as the practice of tracking users has been pushed ever further into the mainstream by major websites and data mining companies; these generally break no known laws and compel users to be tracked, not by fraudulent practices per se , but by

880-399: A local database for kernel-based application functions, and to eliminate the context switches that would otherwise occur when kernel functions interact with a database system running in user mode. Functions are also sometimes moved across rings in the other direction. The Linux kernel, for instance, injects into processes a vDSO section which contains functions that would normally require

968-497: A monolithic kernel , the operating system runs in supervisor mode and the applications run in user mode. Other types of operating systems , like those with an exokernel or microkernel , do not necessarily share this behavior. Some examples from the PC world: Most processors have at least two different modes. The x86 -processors have four different modes divided into four different rings. Programs that run in Ring 0 can do anything with

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1056-448: A new computer because the existing system "has become too slow". Badly infected systems may require a clean reinstallation of all their software in order to return to full functionality. Moreover, some types of spyware disable software firewalls and antivirus software , and/or reduce browser security settings, which opens the system to further opportunistic infections . Some spyware disables or even removes competing spyware programs, on

1144-470: A number of the spyware programs distributed by Claria are collectively known as "Gator". Likewise, programs that are frequently installed together may be described as parts of the same spyware package, even if they function separately. Spyware vendors include NSO Group , which in the 2010s sold spyware to governments for spying on human rights activists and journalists . NSO Group was investigated by Citizen Lab . Malicious programmers have released

1232-534: A point of attachment for spyware in the form of Browser Helper Objects , which modify the browser's behaviour. A spyware program rarely operates alone on a computer; an affected machine usually has multiple infections. Users frequently notice unwanted behavior and degradation of system performance. A spyware infestation can create significant unwanted CPU activity, disk usage, and network traffic. Stability issues, such as applications freezing, failure to boot, and system-wide crashes are also common. Usually, this effect

1320-433: A program in supervisor mode is trusted never to fail, since a failure may cause the whole computer system to crash. Supervisor mode is "an execution mode on some processors which enables execution of all instructions, including privileged instructions. It may also give access to a different address space, to memory management hardware and to other peripherals. This is the mode in which the operating system usually runs." In

1408-409: A secure way towards predefined entry points in lower-level (more trusted) rings; this functions as a supervisor call in many operating systems that use the ring architecture. The hardware restrictions are designed to limit opportunities for accidental or malicious breaches of security. In addition, the most privileged ring may be given special capabilities (such as real memory addressing that bypasses

1496-419: A subroutine in a different section of memory would automatically cause a ring transfer. The hardware severely restricts the ways in which control can be passed from one ring to another, and also enforces restrictions on the types of memory access that can be performed across rings. Using x86 as an example, there is a special gate structure which is referenced by the call instruction that transfers control in

1584-517: A system call, i.e. a ring transition. Instead of doing a syscall these functions use static data provided by the kernel. This avoids the need for a ring transition and so is more lightweight than a syscall. The function gettimeofday can be provided this way. Recent CPUs from Intel and AMD offer x86 virtualization instructions for a hypervisor to control Ring 0 hardware access. Although they are mutually incompatible, both Intel VT-x (codenamed "Vanderpool") and AMD-V (codenamed "Pacifica") allow

1672-527: A user program in Ring 3 should be prevented from turning on a web camera without informing the user, since hardware access should be a Ring 1 function reserved for device drivers . Programs such as web browsers running in higher numbered rings must request access to the network, a resource restricted to a lower numbered ring. X86S, a recently published Intel architecture, has only ring 0 and ring 3. Ring 1 and 2 will be removed under X86S since modern OSes never utilize them. Multiple rings of protection were among

1760-449: A user's control of a computer by installing additional software or redirecting web browsers . Some spyware can change computer settings, which can result in slow Internet connection speeds, un-authorized changes in browser settings, or changes to software settings. Sometimes, spyware is included along with genuine software, and may come from a malicious website or may have been added to the intentional functionality of genuine software (see

1848-792: A variety of companies. These monitor the flow of information going to and from a networked computer and provide protection against spyware and malware. Some users install a large hosts file which prevents the user's computer from connecting to known spyware-related web addresses. Spyware may get installed via certain shareware programs offered for download. Downloading programs only from reputable sources can provide some protection from this source of attack. Individual users can use cellphone / computer with physical (electric) switch, or isolated electronic switch that disconnects microphone, camera without bypass and keep it in disconnected position where not in use, that limits information that spyware can collect. (Policy recommended by NIST Guidelines for Managing

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1936-414: A virtual-machine control. These hardware extensions allow classical "Trap and Emulate" virtualization to perform on x86 architecture but now with hardware support. A privilege level in the x86 instruction set controls the access of the program currently running on the processor to resources such as memory regions, I/O ports, and special instructions. There are 4 privilege levels ranging from 0 which

2024-548: A website wanted to install. The combination of user ignorance about these changes, and the assumption by Internet Explorer that all ActiveX components are benign, helped to spread spyware significantly. Many spyware components would also make use of exploits in JavaScript , Internet Explorer and Windows to install without user knowledge or permission. The Windows Registry contains multiple sections where modification of key values allows software to be executed automatically when

2112-414: Is a type of spyware that is not hidden from the user, but operates with their knowledge, if not necessarily their consent. Parents, religious leaders or other authority figures may require their children or congregation members to install such software, which is intended to detect the viewing of pornography or other content deemed inappropriate, and to report it to the authority figure, who may then confront

2200-623: Is a violation of the terms of service of most affiliate marketing networks. Mobile devices can also be vulnerable to chargeware , which manipulates users into illegitimate mobile charges. In one case, spyware has been closely associated with identity theft . In August 2005, researchers from security software firm Sunbelt Software suspected the creators of the common CoolWebSearch spyware had used it to transmit " chat sessions , user names , passwords , bank information, etc."; however it turned out that "it actually (was) its own sophisticated criminal little trojan that's independent of CWS." This case

2288-420: Is advised for those who are less knowledgeable on this subject to post a HijackThis log on the numerous antispyware sites and let the experts decide what to delete. If a spyware program is not blocked and manages to get itself installed, it may resist attempts to terminate or uninstall it. Some programs work in pairs: when an anti-spyware scanner (or the user) terminates one running process, the other one respawns

2376-409: Is any malware that aims to gather information about a person or organization and send it to another entity in a way that harms the user by violating their privacy , endangering their device's security, or other means. This behavior may be present in other malware and in legitimate software. Websites may engage in spyware behaviors like web tracking . Hardware devices may also be affected. Spyware

2464-457: Is frequently associated with advertising and involves many of the same issues . Because these behaviors are so common, and can have non-harmful uses, providing a precise definition of spyware is a difficult task. The first recorded use of the term spyware occurred on October 16, 1995, in a Usenet post that poked fun at Microsoft 's business model . Spyware at first denoted software meant for espionage purposes. However, in early 2000

2552-597: Is intentional, but may be caused from the malware simply requiring large amounts of computing power, disk space, or network usage. Spyware, which interferes with networking software commonly causes difficulty connecting to the Internet. In some infections, the spyware is not even evident. Users assume in those situations that the performance issues relate to faulty hardware, Windows installation problems, or another malware infection. Some owners of badly infected systems resort to contacting technical support experts, or even buying

2640-463: Is of limited usefulness without regular updates. Updates may be installed automatically or manually. A popular generic spyware removal tool used by those that requires a certain degree of expertise is HijackThis , which scans certain areas of the Windows OS where spyware often resides and presents a list with items to delete manually. As most of the items are legitimate windows files/registry entries it

2728-401: Is one of two or more hierarchical levels or layers of privilege within the architecture of a computer system . This is generally hardware-enforced by some CPU architectures that provide different CPU modes at the hardware or microcode level . Rings are arranged in a hierarchy from most privileged (most trusted, usually numbered zero) to least privileged (least trusted, usually with

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2816-402: Is surreptitiously installed to control a user's computer. In German-speaking countries, spyware used or made by the government is called govware by computer experts (in common parlance: Regierungstrojaner , literally "Government Trojan"). Govware is typically a trojan horse software used to intercept communications from the target computer. Some countries, like Switzerland and Germany, have

2904-481: Is that some hardware architectures that were supported in the past (such as PowerPC or MIPS ) implemented only two privilege levels. Multics was an operating system designed specifically for a special CPU architecture (which in turn was designed specifically for Multics), and it took full advantage of the CPU modes available to it. However, it was an exception to the rule. Today, this high degree of interoperation between

2992-404: Is the most privileged, to 3 which is least privileged. Most modern operating systems use level 0 for the kernel/executive, and use level 3 for application programs. Any resource available to level n is also available to levels 0 to n, so the privilege levels are rings. When a lesser privileged process tries to access a higher privileged process, a general protection fault exception is reported to

3080-440: Is to install, hack into the network, avoid being detected, and safely remove themselves from the network. Spyware is mostly used for the stealing information and storing Internet users' movements on the Web and serving up pop-up ads to Internet users. Whenever spyware is used for malicious purposes, its presence is typically hidden from the user and can be difficult to detect. Some spyware, such as keyloggers , may be installed by

3168-577: The GIANT AntiSpyware software, re‑branding it as Microsoft AntiSpyware (Beta 1) and releasing it as a free download for Genuine Windows XP and Windows 2003 users. In November, 2005, it was renamed Windows Defender . Major anti-virus firms such as Symantec , PC Tools , McAfee and Sophos have also added anti-spyware features to their existing anti-virus products. Early on, anti-virus firms expressed reluctance to add anti-spyware functions, citing lawsuits brought by spyware authors against

3256-758: The Honeywell 6180 , implemented them in hardware, with support for eight rings; Protection rings in Multics were separate from CPU modes; code in all rings other than ring 0, and some ring 0 code, ran in slave mode. However, most general-purpose systems use only two rings, even if the hardware they run on provides more CPU modes than that. For example, Windows 7 and Windows Server 2008 (and their predecessors) use only two rings, with ring 0 corresponding to kernel mode and ring 3 to user mode , because earlier versions of Windows NT ran on processors that supported only two protection levels. Many modern CPU architectures (including

3344-529: The System Management Mode is referred as "ring −2", the Intel Management Engine and AMD Platform Security Processor are sometimes referred as "ring −3". Many CPU hardware architectures provide far more flexibility than is exploited by the operating systems that they normally run. Proper use of complex CPU modes requires very close cooperation between the operating system and

3432-663: The 32-bit address space and reduce dependencies on assembly language, often resulting in substantial increases in functionality, performance and reliability compared with their AOS ancestors. This operating-system -related article is a stub . You can help Misplaced Pages by expanding it . Protection ring In computer science , hierarchical protection domains , often called protection rings , are mechanisms to protect data and functionality from faults (by improving fault tolerance ) and malicious behavior (by providing computer security ). Computer operating systems provide different levels of access to resources. A protection ring

3520-553: The AOS/VS kernel, as well as some I/O buffering and many compatibility functions, ran in ring 3 of each process. Ring 4 was used by various D.G. products such as the INFOS II DBMS . Rings 5 and 6 were reserved for use by user programs but rarely used except for large software such as the MV/UX inner-ring emulator and Oracle which used ring 5. All user programs ran in ring 7. The AOS software

3608-556: The CLI is famous for including an Easter egg meant to honor Xyzzy (which was pronounced "magic"). This was the internal code name of what externally became known as the AOS/VS 32-bit operating system. A user typing in the command " xyzzy " would get back a response from the CLI of "Nothing Happens". When a 32-bit version of the CLI became available under AOS/VS II , the same command instead reported "Twice As Much Happens". A modified version of System V.2 Unix called MV/UX hosted under AOS/VS

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3696-486: The CPU, and thus tends to tie the OS to the CPU architecture. When the OS and the CPU are specifically designed for each other, this is not a problem (although some hardware features may still be left unexploited), but when the OS is designed to be compatible with multiple, different CPU architectures, a large part of the CPU mode features may be ignored by the OS. For example, the reason Windows uses only two levels (ring 0 and ring 3)

3784-557: The IOPL in order for the task or program to access I/O ports . The IOPL can be changed using POPF(D) and IRET(D) only when the current privilege level is Ring 0. Besides IOPL, the I/O Port Permissions in the TSS also take part in determining the ability of a task to access an I/O port. In x86 systems, the x86 hardware virtualization ( VT-x and SVM ) is referred as "ring −1",

3872-563: The National Cyber-Security Alliance, 61 percent of surveyed users' computers were infected with some form of spyware. 92 percent of surveyed users with spyware reported that they did not know of its presence, and 91 percent reported that they had not given permission for the installation of the spyware. As of 2006 , spyware has become one of the preeminent security threats to computer systems running Microsoft Windows operating systems . Computers on which Internet Explorer (IE)

3960-413: The OS and the hardware is not often cost-effective, despite the potential advantages for security and stability. Ultimately, the purpose of distinct operating modes for the CPU is to provide hardware protection against accidental or deliberate corruption of the system environment (and corresponding breaches of system security) by software. Only "trusted" portions of system software are allowed to execute in

4048-518: The OS. It is not necessary to use all four privilege levels. Current operating systems with wide market share including Microsoft Windows , macOS , Linux , iOS and Android mostly use a paging mechanism with only one bit to specify the privilege level as either Supervisor or User (U/S Bit). Windows NT uses the two-level system. The real mode programs in 8086 are executed at level 0 (highest privilege level) whereas virtual mode in 8086 executes all programs at level 3. Potential future uses for

4136-522: The Security of Mobile Devices, 2013). A few spyware vendors, notably 180 Solutions , have written what the New York Times has dubbed " stealware ", and what spyware researcher Ben Edelman terms affiliate fraud , a form of click fraud . Stealware diverts the payment of affiliate marketing revenues from the legitimate affiliate to the spyware vendor. Spyware which attacks affiliate networks places

4224-460: The actual switch (70 from user to kernel space, and 40 back), the rest is "kernel overhead". In the L3 microkernel , the minimization of this overhead reduced the overall cost to around 150 cycles. Maurice Wilkes wrote: ... it eventually became clear that the hierarchical protection that rings provided did not closely match the requirements of the system programmer and gave little or no improvement on

4312-554: The authors of web sites and programs which described their products as "spyware". However, recent versions of these major firms home and business anti-virus products do include anti-spyware functions, albeit treated differently from viruses. Symantec Anti-Virus, for instance, categorizes spyware programs as "extended threats" and now offers real-time protection against these threats. Other Anti-spyware tools include FlexiSPY, Mobilespy, mSPY, TheWiSPY, and UMobix. Anti-spyware programs can combat spyware in two ways: Such programs inspect

4400-718: The chance of getting spyware on a system. Nonetheless, spyware remains a costly problem. When a large number of pieces of spyware have infected a Windows computer, the only remedy may involve backing up user data, and fully reinstalling the operating system . For instance, some spyware cannot be completely removed by Symantec, Microsoft, PC Tools. Many programmers and some commercial firms have released products designed to remove or block spyware. Programs such as PC Tools' Spyware Doctor , Lavasoft's Ad-Aware SE and Patrick Kolla's Spybot - Search & Destroy rapidly gained popularity as tools to remove, and in some cases intercept, spyware programs. In December 2004, Microsoft acquired

4488-487: The computer. A typical Windows user has administrative privileges , mostly for convenience. Because of this, any program the user runs has unrestricted access to the system. As with other operating systems , Windows users are able to follow the principle of least privilege and use non- administrator accounts. Alternatively, they can reduce the privileges of specific vulnerable Internet-facing processes , such as Internet Explorer . Since Windows Vista is, by default,

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4576-640: The contents of the Windows registry , operating system files, and installed programs , and remove files and entries which match a list of known spyware. Real-time protection from spyware works identically to real-time anti-virus protection: the software scans disk files at download time, and blocks the activity of components known to represent spyware. In some cases, it may also intercept attempts to install start-up items or to modify browser settings. Earlier versions of anti-spyware programs focused chiefly on detection and removal. Javacool Software's SpywareBlaster , one of

4664-529: The current ring of the executing instruction thread at all times, with the help of a special machine register. In some systems, areas of virtual memory are instead assigned ring numbers in hardware. One example is the Data General Eclipse MV/8000 , in which the top three bits of the program counter (PC) served as the ring register. Thus code executing with the virtual PC set to 0xE200000, for example, would automatically be in ring 7, and calling

4752-673: The default settings created for users and the language of terms-of-service agreements. In one documented example, on CBS/CNet News reported, on March 7, 2011, an analysis in The Wall Street Journal revealed the practice of Facebook and other websites of tracking users' browsing activity , which is linked to their identity, far beyond users' visits and activity on the Facebook site itself. The report stated: "Here's how it works. You go to Facebook, you log in, you spend some time there, and then ... you move on without logging out. Let's say

4840-429: The first to offer real-time protection, blocked the installation of ActiveX -based spyware. Like most anti-virus software, many anti-spyware/adware tools require a frequently updated database of threats. As new spyware programs are released, anti-spyware developers discover and evaluate them, adding to the list of known spyware, which allows the software to detect and remove new spyware. As a result, anti-spyware software

4928-536: The founder of Zone Labs , Gregor Freund, used the term in a press release for the ZoneAlarm Personal Firewall . Later in 2000, a parent using ZoneAlarm was alerted to the fact that Reader Rabbit , educational software marketed to children by the Mattel toy company, was surreptitiously sending data back to Mattel. Since then, "spyware" has taken on its present sense. According to a 2005 study by AOL and

5016-480: The grounds that more spyware-related annoyances increase the likelihood that users will take action to remove the programs. Keyloggers are sometimes part of malware packages downloaded onto computers without the owners' knowledge. Some keylogger software is freely available on the internet, while others are commercial or private applications. Most keyloggers allow not only keyboard keystrokes to be captured, they also are often capable of collecting screen captures from

5104-601: The highest ring number). On most operating systems, Ring 0 is the level with the most privileges and interacts most directly with the physical hardware such as certain CPU functionality (e.g. the control registers) and I/O controllers. Special mechanisms are provided to allow an outer ring to access an inner ring's resources in a predefined manner, as opposed to allowing arbitrary usage. Correctly gating access between rings can improve security by preventing programs from one ring or privilege level from misusing resources intended for programs in another. For example, spyware running as

5192-560: The kernel, drivers and applications typically run on ring 3 (however, this is exclusive to the case where protected-mode drivers or DOS extenders are used; as a real-mode OS, the system runs with effectively no protection), whereas 386 memory managers such as EMM386 run at ring 0. In addition to this, DR-DOS ' EMM386 3.xx can optionally run some modules (such as DPMS ) on ring 1 instead. OpenVMS uses four modes called (in order of decreasing privileges) Kernel, Executive, Supervisor and User. A renewed interest in this design structure came with

5280-440: The killed program. Likewise, some spyware will detect attempts to remove registry keys and immediately add them again. Usually, booting the infected computer in safe mode allows an anti-spyware program a better chance of removing persistent spyware. Killing the process tree may also work. To detect spyware, computer users have found several practices useful in addition to installing anti-spyware programs. Many users have installed

5368-585: The most revolutionary concepts introduced by the Multics operating system, a highly secure predecessor of today's Unix family of operating systems. The GE 645 mainframe computer did have some hardware access control, including the same two modes that the other GE-600 series machines had, and segment-level permissions in its memory management unit ("Appending Unit"), but that was not sufficient to provide full support for rings in hardware, so Multics supported them by trapping ring transitions in software; its successor,

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5456-530: The multiple privilege levels supported by the x86 ISA family include containerization and virtual machines . A host operating system kernel could use instructions with full privilege access ( kernel mode ), whereas applications running on the guest OS in a virtual machine or container could use the lowest level of privileges in user mode. The virtual machine and guest OS kernel could themselves use an intermediate level of instruction privilege to invoke and virtualize kernel-mode operations such as system calls from

5544-435: The next site you go to is The New York Times . Those buttons, without you clicking on them, have just reported back to Facebook and Twitter that you went there and also your identity within those accounts. Let's say you moved on to something like a site about depression. This one also has a tweet button, a Google widget, and those, too, can report back who you are and that you went there." The Wall Street Journal analysis

5632-422: The operating system boots. Spyware can exploit this design to circumvent attempts at removal. The spyware typically links itself to each location in the registry that allows execution. Once running, the spyware will periodically check if any of these links are removed. If so, they will be automatically restored. This ensures that the spyware will execute when the operating system is booted, even if some (or most) of

5720-871: The operating system. Operating systems designed to work on multiple hardware platforms may make only limited use of rings if they are not present on every supported platform. Often the security model is simplified to "kernel" and "user" even if hardware provides finer granularity through rings. In computer terms, supervisor mode is a hardware-mediated flag that can be changed by code running in system-level software. System-level tasks or threads may have this flag set while they are running, whereas user-level applications will not. This flag determines whether it would be possible to execute machine code operations such as modifying registers for various descriptor tables, or performing operations such as disabling interrupts. The idea of having two different modes to operate in comes from "with more power comes more responsibility" –

5808-428: The owner of a shared, corporate, or public computer intentionally in order to monitor users. While the term spyware suggests software that monitors a user's computer, the functions of spyware can extend beyond simple monitoring. Spyware can collect almost any type of data, including personal information like internet surfing habits, user logins, and bank or credit account information. Spyware can also interfere with

5896-400: The paragraph about Facebook , below). In response to the emergence of spyware, a small industry has sprung up dealing in anti-spyware software. Running anti-spyware software has become a widely recognized element of computer security practices, especially for computers running Microsoft Windows . A number of jurisdictions have passed anti-spyware laws, which usually target any software that

5984-505: The point of view of the guest operating system. The IOPL ( I/O Privilege level ) flag is a flag found on all IA-32 compatible x86 CPUs . It occupies bits 12 and 13 in the FLAGS register . In protected mode and long mode , it shows the I/O privilege level of the current program or task. The Current Privilege Level (CPL) (CPL0, CPL1, CPL2, CPL3) of the task or program must be less than or equal to

6072-457: The popular Intel x86 architecture) include some form of ring protection, although the Windows NT operating system, like Unix, does not fully utilize this feature. OS/2 does, to some extent, use three rings: ring 0 for kernel code and device drivers, ring 2 for privileged code (user programs with I/O access permissions), and ring 3 for unprivileged code (nearly all user programs). Under DOS ,

6160-536: The proliferation of the Xen VMM software, ongoing discussion on monolithic vs. micro-kernels (particularly in Usenet newsgroups and Web forums ), Microsoft's Ring-1 design structure as part of their NGSCB initiative, and hypervisors based on x86 virtualization such as Intel VT-x (formerly Vanderpool). The original Multics system had eight rings, but many modern systems have fewer. The hardware remains aware of

6248-545: The reason above, VT-x and AMD-V allow the guest to run under Ring 0. VT-x introduces VMX Root/Non-root Operation: The hypervisor runs in VMX Root Operation mode, possessing the highest privilege. Guest OS runs in VMX Non-Root Operation mode, which allows them to operate at ring 0 without having actual hardware privileges. VMX non-root operation and VMX transitions are controlled by a data structure called

6336-433: The registry links are removed. Spyware is mostly classified into four types: adware , system monitors, tracking including web tracking , and trojans ; examples of other notorious types include digital rights management capabilities that "phone home", keyloggers , rootkits , and web beacons . These four categories are not mutually exclusive and they have similar tactics in attacking networks and devices. The main goal

6424-770: The simple system of having two modes only. Rings of protection lent themselves to efficient implementation in hardware, but there was little else to be said for them. [...] The attractiveness of fine-grained protection remained, even after it was seen that rings of protection did not provide the answer... This again proved a blind alley... To gain performance and determinism, some systems place functions that would likely be viewed as application logic, rather than as device drivers, in kernel mode; security applications ( access control , firewalls , etc.) and operating system monitors are cited as examples. At least one embedded database management system, e X treme DB Kernel Mode , has been developed specifically for kernel mode deployment, to provide

6512-472: The spyware author, the page contains code which attacks the browser and forces the download and installation of spyware. The installation of spyware frequently involves Internet Explorer . Its popularity and history of security issues have made it a frequent target. Its deep integration with the Windows environment make it susceptible to attack into the Windows operating system . Internet Explorer also serves as

6600-405: The spyware operator's affiliate tag on the user's activity – replacing any other tag, if there is one. The spyware operator is the only party that gains from this. The user has their choices thwarted, a legitimate affiliate loses revenue, networks' reputations are injured, and vendors are harmed by having to pay out affiliate revenues to an "affiliate" who is not party to a contract. Affiliate fraud

6688-463: The system, and code that runs in Ring 3 should be able to fail at any time without impact to the rest of the computer system. Ring 1 and Ring 2 are rarely used, but could be configured with different levels of access. In most existing systems, switching from user mode to kernel mode has an associated high cost in performance. It has been measured, on the basic request getpid , to cost 1000–1500 cycles on most machines. Of these just around 100 are for

6776-576: The transition is from a level of high privilege to one of low privilege (as from kernel to user modes), but transitions from lower to higher levels of privilege can take place only through secure, hardware-controlled "gates" that are traversed by executing special instructions or when external interrupts are received. Microkernel operating systems attempt to minimize the amount of code running in privileged mode, for purposes of security and elegance , but ultimately sacrificing performance. Spyware Spyware (a portmanteau for spying software )

6864-434: The unrestricted environment of kernel mode, and then, in paradigmatic designs, only when absolutely necessary. All other software executes in one or more user modes. If a processor generates a fault or exception condition in a user mode, in most cases system stability is unaffected; if a processor generates a fault or exception condition in kernel mode, most operating systems will halt the system with an unrecoverable error. When

6952-421: The user about it. These common spyware programs illustrate the diversity of behaviors found in these attacks. Note that as with computer viruses, researchers give names to spyware programs which may not be used by their creators. Programs may be grouped into "families" based not on shared program code, but on common behaviors, or by "following the money" of apparent financial or business connections. For instance,

7040-786: The virtual memory hardware). ARM version 7 architecture implements three privilege levels: application (PL0), operating system (PL1), and hypervisor (PL2). Unusually, level 0 (PL0) is the least-privileged level, while level 2 is the most-privileged level. ARM version 8 implements four exception levels: application (EL0), operating system (EL1), hypervisor (EL2), and secure monitor / firmware (EL3), for AArch64 and AArch32. Ring protection can be combined with processor modes (master/kernel/privileged/ supervisor mode versus slave/unprivileged/user mode) in some systems. Operating systems running on hardware supporting both may use both forms of protection or only one. Effective use of ring architecture requires close cooperation between hardware and

7128-538: Was found to be using rootkits in its XCP digital rights management technology Like spyware, not only was it difficult to detect and uninstall, it was so poorly written that most efforts to remove it could have rendered computers unable to function. Texas Attorney General Greg Abbott filed suit, and three separate class-action suits were filed. Sony BMG later provided a workaround on its website to help users remove it. Beginning on April 25, 2006, Microsoft's Windows Genuine Advantage Notifications application

7216-684: Was also available. A modified version of System V Unix called DG/UX was made for the Eclipse MV line and later the 88K and x86 AViiON machines. The AOS and AOS/VS kernels were written entirely in assembly language . Almost all of the AOS and AOS/VS utilities included in the operating system releases were written in DG/L a variant of the ALGOL/60 programming language. Initially, AOS/VS utilities closely tracked AOS source development. As AOS/VS matured, many DG-supplied utilities were rewritten to take advantage of

7304-403: Was far more advanced than competing PDP-11 operating systems. 16-bit AOS applications ran natively under AOS/VS and AOS/VS II on the 32-bit Eclipse MV line. AOS/VS (Advanced Operating System/Virtual Storage) was the most commonly used DG software product, and included a command-line interpreter (CLI) allowing for complex scripting, DUMP/LOAD, and other custom components. The 16-bit version of

7392-578: Was installed on most Windows PCs as a "critical security update". While the main purpose of this deliberately uninstallable application is to ensure the copy of Windows on the machine was lawfully purchased and installed, it also installs software that has been accused of " phoning home " on a daily basis, like spyware. It can be removed with the RemoveWGA tool. Stalkerware is spyware that has been used to monitor electronic activities of partners in intimate relationships. At least one software package, Loverspy,

7480-484: Was investigated by the FBI . The Federal Trade Commission estimates that 27.3 million Americans have been victims of identity theft, and that financial losses from identity theft totaled nearly $ 48 billion for businesses and financial institutions and at least $ 5 billion in out-of-pocket expenses for individuals. Some copy-protection technologies have borrowed from spyware. In 2005, Sony BMG Music Entertainment

7568-539: Was researched by Brian Kennish, founder of Disconnect, Inc. Spyware does not necessarily spread in the same way as a virus or worm because infected systems generally do not attempt to transmit or copy the software to other computers. Instead, spyware installs itself on a system by deceiving the user or by exploiting software vulnerabilities. Most spyware is installed without knowledge, or by using deceptive tactics. Spyware may try to deceive users by bundling itself with desirable software. Other common tactics are using

7656-763: Was specifically marketed for this purpose. Depending on local laws regarding communal/marital property, observing a partner's online activity without their consent may be illegal; the author of Loverspy and several users of the product were indicted in California in 2005 on charges of wiretapping and various computer crimes. Anti-spyware programs often report Web advertisers' HTTP cookies , the small text files that track browsing activity, as spyware. While they are not always inherently malicious, many users object to third parties using space on their personal computers for their business purposes, and many anti-spyware programs offer to remove them. Shameware or " accountability software "

7744-419: Was the primary browser are particularly vulnerable to such attacks, not only because IE was the most widely used, but also because its tight integration with Windows allows spyware access to crucial parts of the operating system. Before Internet Explorer 6 SP2 was released as part of Windows XP Service Pack 2 , the browser would automatically display an installation window for any ActiveX component that

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