W32/Rbot-GUR is a worm with IRC backdoor functionality for the Windows platform.
W32/Rbot-GUR runs continuously in the background, providing a backdoor server which allows a remote intruder to gain access and control over the computer via IRC channels.
When first run W32/Rbot-GUR copies itself to <System>\nlczty.exe.
The following registry entries are created to run nlczty.exe on startup:
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Microsoft Update Machine
nlczty.exe
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
Microsoft Update Machine
nlczty.exe
W32/Rbot-GUR sets the following registry entries, disabling the automatic startup of other software:
HKLM\SYSTEM\CurrentControlSet\Services\wuauserv
Start
4
HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess
Start
4
Note: disabling autostart for the SharedAccess service deactivates the Microsoft Internet Connection Firewall (ICF).
Registry entries are set as follows:
HKCU\Software\Microsoft\OLE
Microsoft Update Machine
nlczty.exe
HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings
MaxConnectionsPer1_0Server
50
HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings
MaxConnectionsPerServer
50
HKLM\SOFTWARE\Microsoft\Ole
EnableDCOM
N