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Backdoor:Win32/Zegost.AK


Backdoor:Win32/Zegost.AK is a trojan that allows unauthorized access and control of an affected computer.


What to do now

To detect and remove this threat and other malicious software that may have been installed in your computer, run a full-system scan with an up-to-date antivirus product such as the following: For more information about using antivirus software, see http://www.microsoft.com/windows/antivirus-partners/.

Threat behavior

Backdoor:Win32/Zegost.AK is a trojan that allows unauthorized access and control of an affected computer.
Installation
When executed, Backdoor:Win32/Zegost.AK copies itself to <system folder>\runr.exe.

Note: <system folder> refers to a variable location that is determined by the malware by querying the Operating System. The default installation location for the System folder for Windows 2000 and NT is C:\Winnt\System32; and for XP, Vista, and 7 is C:\Windows\System32.

The malware modifies the following registry entries to ensure that its copy executes at each Windows start:

Adds value: "zxcd"
With data: "c:\windows\system32\runr.exe"
To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Payload
Allows backdoor access and control
Backdoor:Win32/Zegost.AK allows unauthorized access and control of an affected computer. An attacker can perform any number of different actions on an affected computer using Backdoor:Win32/Zegost.AK. This could include, but is not limited to, the following actions:

  • Download and execute arbitrary files
  • Upload files
  • Spread to other computers using various methods of propagation
  • Log keystrokes or steal sensitive data
  • Modify system settings
  • Run or terminate applications
  • Delete files

This malware description was produced and published using our automated analysis system's examination of file SHA1 e5f32e79d8c0b51f690edc19e00671195a6617a5.

Symptoms

System changes
The following system changes may indicate the presence of this malware:

  • The presence of the following files:

  • <system folder>\runr.exe

  • The presence of the following registry modifications:
  • Adds value: "zxcd"
    With data: "c:\windows\system32\runr.exe"
    To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run


Prevention


Alert level: Severe
First detected by definition: 1.135.692.0
Latest detected by definition: 1.183.338.0 and higher
First detected on: Sep 07, 2012
This entry was first published on: Sep 13, 2012
This entry was updated on: Sep 14, 2012

This threat is also detected as:
  • Trojan.Win32.Jorik.Yoddos.ro (Kaspersky)