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Win32.Worm.Korgo.A,B

First posted on 21 November 2011.
Source: BitDefender

Aliases :

Win32.Worm.Korgo.A,B is also known as Korgo.

Explanation :

The worm exploits the Microsoft LSASS Windows vulnerability for spreading.
http://www.microsoft.com/technet/security/bulletin/MS04-011.mspx

Once run, the worm will do the following:

1. Attempts to delete Go.exe from current location

2. Creates the mutexes:

variant A: r10, rocket10
variant B: r10, u2, uterm5

3. Checks if the [HKLM SOFTWAREMicrosoftWindowsCurrentVersionRun"WinUpdate"] entry exists

If the key exists:

Attempts to delete the registry entry: [HKLMSoftwareMicrosoftWireless"Server"]

If the key doesn't exist, it attempts to create it:

[HKLMSoftwareMicrosoftWireless"Server"="1"]

4. Creates a randomly named copy of the worm in %SYSTEM% folder, as ????????.exe where ? may be any letter.

5. Creates the registry entry

[HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun"WinUpdate"="%SYSTEM%????????.exe"]

in order to run at startup.

6. Executes the copy of the worm and terminates the current process.

7. Starts many threads, and enters an infinite loop, preventing the system from shutting down.

8. Opens ports: 113, 3067, 2041, allowing remote connection and for sending the worm, scans random IP addresses in order to infect unpatched systems.
Also opens port 6667, as it attempts to connect to a list of IRC servers where it listens for commands

Last update 21 November 2011

 

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