Korgo (aka Padobot) is a network worm written by the Russian Hangup Team virus group. It spreads throughout the Internet using a vulnerability in Microsoft Windows LSASS. A description of the vulnerability can be found in Microsoft Security Bulletin MS04-011: https://www.microsoft.com/technet/security/bulletin/MS04-011.mspx
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
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The worm is written in C++ and is approximately 10KB in size, packed using UPX.
When launching, the worm copies itself to the Windows system directory under a random name, and registers this file in the system registry auto-run key:
- [HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run] WinUpdate = %system%\name of file
It also creates a registry key
- HKLM\SOFTWARE\Microsoft\Wireless Server = 1
It creates the mutexes "10", "u2" and "uterm5" to flag its presence in the system. The worm chooses the IP-addresses of random machines to infect and attack, similar to other worms which exploit the same LSASS vulnerability.
Once infected, a victim machine will display an error message that the LSASS service has failed. After this error message has been displayed, the computer may reboot.
The worm open TCP ports 113, 3067 and 2041 to receive commands.
It attempts to connect to several IRC servers to receive commands and transmit data.