The security engineers and IT experts from the Comodo Antivirus Labs are constantly analyzing the thousands of malware families that are trying to cause destruction and chaos to IT infrastructures large and small – and ensuring the customers of Comodo stay protected and secure from these malware families.


In an ongoing series of posts here at, the security experts at Comodo will look at a specific malware family and stack it up against Comodo’s advanced  endpoint protection and containment technology, and talk about the how why Comodo’s technology defeats all malware.   Comodo Senior Vice President of Engineering Egemen Tas and Director of Threat Research Igor Demihovskiy offered their perspectives for this week’s post:


How do file infectors like Ramnit work?

File infectors are among the oldest types of viruses, yet hackers keep them relevant by introducing new variants with more sophisticated behaviors.

Once Ramnit is dropped into a host system via flash drive, email, web page exploit or malvertising, it begins searching for executable files.   When it finds one it attempts to inject its payload, rewriting the program’s code so that the malware activates every time the infected program runs, and spreads to other executables as well.  Once active, the malware may simply steal any files it decides might contain sensitive information like passwords, credit card numbers, personal data, etc.  Newer variants may employ more sophisticated attacks.

Why file infectors are still effective:

Each new variant of these viruses represents a zero-day threat that traditional antivirus technology might not detect until it’s too late.  Some variants attempt to hide themselves from detection using techniques like encryption, which makes the code look meaningless (and therefore innocuous) to signature-based antivirus programs.

Comodo contains the virus:

Comodo’s advanced containment technology automatically runs ALL unknown files in a virtual container, separating them from the protected system so they can’t do damage to existing code, registry, etc.  While a contained virus can READ directly from disk (c:\xxx.exe), copy-on-write protection redirects the action to a virtual drive when it attempts to WRITE its payload to disk (c:\VTroot\c:\xxx.exe).  In this way, viruses like Ramnit are contained the instant they start up and are never allowed the unfettered system access they need to rewrite files on hard disk.

Comodo analyzes and quarantines the virus:

Once contained, the file is analyzed in the sandbox using both traditional and advanced techniques like dynamic analysis, heuristics, reputation analysis and, if necessary, expert human intervention. The status of the virus is then moved from “Unknown” to “Known Bad,” at which point it is quarantined and dealt with per administrator policy. When the process is complete the virtual container is deleted from active memory, along with everything inside of it.

If you feel your company’s IT environment is under attack from phishing, malware, spyware or cyberattacks, contact the security consultants at our Comodo Antivirus Labs: