BKDR_DESTOVER.C
Backdoor.Destover (Symantec), Trojan:Win32/NukeSped.D!dha (Micosoft), Trojan.Win32.Destover.e (Kasprsky)
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It executes commands from a remote malicious user, effectively compromising the affected system.
TECHNICAL DETAILS
Arrival Details
This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Installation
This backdoor drops the following copies of itself into the affected system and executes them:
- {root directory of initial folder}:\igfxconf.exe
Autostart Technique
This backdoor creates the following registry entries to enable automatic execution of dropped component at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
CurrentVersion\Run
IgfxConf = ""{root directory of initial folder}:\igfxconf.exe" /s"
HKEY_CURRENT_USER\Software\Microsoft\
CurrentVersion\Run
IgfxConf = ""{root directory of initial folder}:\igfxconf.exe" /s"
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Rename specified file or move to another directory
- Send the type of each logical drive in the affected system
- Download arbitrary files
- Upload arbitrary files
- Execute arbitrary files
- Check for a specified file's existence
- Terminate specified process
- Send computer name and operating system version
- Uninstall itself (including registry)
- Steal archive files with certain extensions (.Z, .zip, .zoo, .arc, .lzh, .arj, .gz, .tgz)
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- {BLOCKED}.{BLOCKED}.81.73:444
- {BLOCKED}.{BLOCKED}.71.18:444
- {BLOCKED}.{BLOCKED}.112.69:443
- {BLOCKED}.{BLOCKED}.20.68:443
NOTES:
The initial folder is the malware's location when it arrives in the affected system.
It checks for the existence of the following files:
- c_1226705.nls
It first adds its Autostart registry to HKEY_LOCAL_MACHINE. If it fails, it will add it to HKEY_CURRENT_USER instead.
SOLUTION
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Restart in Safe Mode
Step 3
Delete this registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\CurrentVersion\Run
- IgfxConf = ""{root directory of initial folder}:\igfxconf.exe" /s"
- IgfxConf = ""{root directory of initial folder}:\igfxconf.exe" /s"
- In HKEY_CURRENT_USER\Software\Microsoft\CurrentVersion\Run
- IgfxConf = ""{root directory of initial folder}:\igfxconf.exe" /s"
- IgfxConf = ""{root directory of initial folder}:\igfxconf.exe" /s"
Step 4
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_DESTOVER.C. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
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