Antivirus (Cyber Forensics)

What is Antivirus?

Antivirus software (abbreviated to AV software) is a computer program that detects, prevents, and eliminates malware. Antivirus software, as the name implies, was intended to detect and eliminate computer infections. Antivirus software began to protect against additional computer risks as other malware became more prevalent. Modern antivirus software can defend users against harmful browser helper objects (BHOs), browser hijackers, ransomware, keyloggers, backdoors, rootkits, trojan horses, worms, malicious LSPs, dialers, fraud tools, adware, and spyware, among other threats. Certain programs also protect against other computer threats such as infected and malicious URLs, spam, scam and phishing attacks, online identity (privacy), online banking attacks, social engineering techniques, advanced persistent threat (APT), and botnet DDoS attacks.

Also Read: Computer Virus

Identification methods

Frederick B, Cohen’s 1987 proof that no algorithm can completely detect all conceivable viruses is one of the few solid theoretical results in the research of computer viruses. However, by employing many levels of security, a high detection rate can be attained.

Antivirus engines can detect malware using a variety of approaches, including:

  • Sandbox detection:

A behavioral-based detection technique that, rather than detecting the behavioral fingerprint at run time, executes programs in a virtual environment and logs the actions they take. The antivirus engine can assess whether or not the program is malicious based on the actions logged. If this is not the case, the application is run in the real world. Even though this technique has proven to be extremely successful, it is rarely employed in end-user antivirus solutions due to its heaviness and slowness.

  • Data mining techniques:

One of the most recent ways to malware detection Given a set of file features collected from the file, data mining, and machine learning methods are used to try to identify the behavior of the file (as malicious or benign).

Signature-based detection

When it comes to detecting malware, traditional antivirus software mainly depends on signatures. When a malware sample reaches the hands of an antivirus company, it is thoroughly examined by malware researchers or dynamic analysis systems. After it has been confirmed that the file is malware, an appropriate signature of the file is extracted and added to the antivirus software’s signature database.

Although signature-based approaches can effectively contain malware outbreaks, malware authors have attempted to stay one step ahead of such software by creating “oligotrophic,” “polymorphic,” and, more recently, “metamorphic” viruses, which encrypt parts of themselves or otherwise modify themselves to avoid matching virus signatures in the dictionary.


Many viruses begin as a single infection and can evolve into dozens of slightly different strains, known as variations, through mutation or refinement by other attackers. The detection and elimination of multiple threats using a single viral definition are referred to as generic detection.

Depending on the antivirus vendor’s classification, the Vundo trojan, for example, has numerous family members. Members of the Vundo family are divided into two groups by Symantec: Trojan and Virus. Vundo and Trojan are two characters. Vundo. B.

While identifying a single virus may be advantageous, detecting a virus family using a generic signature or an inexact match to an existing signature can be faster. Virus researchers can establish a single generic signature by identifying common locations that all viruses in a family share. Non-contiguous code is frequently used in these signatures, with wildcard characters used where differences exist. These wildcards enable the scanner to discover infections that are padded with nonsensical code. Heuristic detection is a term used to describe a detection that employs this strategy.

Rootkit detection

Rootkits can be scanned for by antivirus software. A rootkit is a form of malware that aims to obtain administrative control of a computer system while remaining undetected. Rootkits can tamper with the operating system’s functionality and, in some situations, render anti-virus software ineffective. Rootkits are also difficult to remove, necessitating a complete reinstall of the operating system in some situations.

Real-time protection

The automatic protection provided by most antivirus, anti-spyware, and other anti-malware products is referred to as real-time protection, on-access scanning, background guard, resident shield, auto-protect, and other synonyms. This software keeps track of suspicious activities on computers, such as computer viruses, spyware, adware, and other harmful software. Real-time protection examines apps as they are installed on the device and detects risks in opened files. When a CD is inserted, an email is opened, a web page is visited, or when a file currently on the computer is opened or run.

How does antivirus work?

Antivirus software works by comparing the files and programs on your computer to a database of known malware types. Because hackers are continually creating and disseminating new viruses, they will also check systems for the presence of new or undiscovered malware threats. Most programs will use one of three detection methods: specific detection, which searches for known malware; generic detection, which searches for known parts or types of malware or patterns that share a common codebase; or heuristic detection, which searches for unknown viruses by identifying known suspicious file structures. When the program discovers a virus-infected file, it will usually quarantine it and/or mark it for deletion, making it inaccessible and removing the threat to your device.

System and interoperability related issues

Multiple antivirus apps (that provide real-time protection) running at the same time can decrease performance and cause conflicts. Several businesses, including G Data Software and Microsoft, have developed software that can run numerous engines at the same time utilizing a concept known as multi scanning. When installing large upgrades like Windows Service Packs or graphics card drivers, it’s occasionally necessary to temporarily stop virus protection.

Active antivirus defense may prevent the installation of a big update in part or entirely. Anti-virus software might cause issues during an operating system upgrade, such as when upgrading to a newer version of Windows “in place”—that is, without uninstalling the prior version of Windows. Anti-virus software should be turned off to minimize issues with the upgrade installation procedure, according to Microsoft. Active anti-virus software can potentially obstruct the firmware upgrade procedure.

Active anti-virus software can interfere with the operation of a few computer apps. True Crypt, a disc encryption program, for example, notes on its troubleshooting page that anti-virus programs can cause True Crypt to malfunction or run very slowly. Antivirus software might degrade the performance and stability of Steam games.

Antivirus program interoperability with standard solutions such as SSL VPN remote access and network access control devices has also been a source of support concerns. These technology solutions often have policy assessment applications that require an up-to-date antivirus to be installed and running.

New viruses

Anti-virus programs, especially ones that use non-signature-based approaches to detect new viruses, are not always effective against new viruses. The reason for this is that before releasing a new virus into the world, virus creators test it against the major anti-virus apps to ensure that it is not identified.

Polymorphic code is used by several emerging infections, particularly ransomware, to prevent detection by virus scanners. According to Jerome Segura, a security analyst at ParetoLogic, It’s something they frequently overlook since this form of [ransomware infection] originates from sites that employ polymorphism, which means they essentially randomize the file they send you, allowing it to slip past even the most sophisticated antivirus software.


Anti-virus software has a difficult time detecting rootkits. Rootkits have full administrative access to the computer, are invisible to users, and are not listed in the task manager’s list of ongoing processes. Rootkits can interfere with antivirus software and change the inner workings of the operating system.

Damaged files

Anti-virus software will attempt to delete the virus code from a file that has been infected by a computer virus during disinfection, but it is not always successful in restoring the file to its original state. Damaged files may only be restored from backups or shadow copies in this kind of case.

Performance and other drawbacks

Antivirus software has some drawbacks, the first of which is that it might slow down a computer.

Furthermore, unskilled users may be lulled into a false feeling of security when using the computer, believing their PCs to be invulnerable, and may struggle to understand the prompts and decisions presented by antivirus software. A blunder in judgment could result in a security breach. If the antivirus software uses heuristic detection, it must be fine-tuned to prevent harmless software from being misidentified as harmful (false positive).

Antivirus software typically runs at the operating system’s highly trusted kernel level, giving it access to all potentially dangerous processes and files, opening up a potential attack vector.

The National Security Agency (NSA) in the United States and the Government Communications Headquarters (GCHQ) in the United Kingdom have both used anti-virus software to spy on users. Antivirus software has privileged and trusted access to the underlying operating system, making it an attractive target for remote assaults. Anti-virus software is also required “Client-side applications like browsers and document readers are years behind in terms of security. It indicates that Acrobat Reader, Microsoft Word, and Google Chrome are more difficult to attack than 90% of anti-virus software “According to Joxean Koret of Coseinc, a Singapore-based information security company.

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