BKDR_SIMBOT.SMAZ
Backdoor:Win32/Simbot.gen (Microsoft); Trojan.Gen (Symantec); Trojan.Win32.Inject.elcw (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Gen:Trojan.Heur.RP.cy0@a08gsQob (FSecure)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This backdoor may be dropped by other malware.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
Arrival Details
This backdoor may be dropped by the following malware:
- TROJ_MDROPP.ZZXX
Installation
This backdoor drops the following copies of itself into the affected system:
- %Local Settings%\rpacpd.exe
It adds the following processes:
- svchost.exe
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random service name} = "%Local Settings%\rpacpd.exe"
Other Details
This backdoor deletes the initially executed copy of itself
NOTES:
It injects the malware BKDR_SIMBOT.SMC to the newly created process.
It searches for the presence of the following registry key:
- SOFTWARE\McAfee
If the registry exists, it will execute the alternate routines listed below:
- It will create a different process:
- services.exe
- Drops a copy of itself using the file below:
- %Local Settings%\NtLmSsp.exe
- It will add a different autostart registry as well:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\
CurrentVersion\Run
{random service name} = "Local Settings%\NtLmSsp.exe"
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
Remove malware/grayware files that dropped/downloaded BKDR_SIMBOT.SMAZ
Step 3
Scan your computer with your Trend Micro product and note files detected as BKDR_SIMBOT.SMAZ
Step 4
Restart in Safe Mode
Step 5
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_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- {random service name} = "%Local Settings%\rpacpd.exe"
- {random service name} = "%Local Settings%\rpacpd.exe"
- In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- {random service name} = "%Local Settings%\NtLmSsp.exe"
- {random service name} = "%Local Settings%\NtLmSsp.exe"
Step 6
Search and delete the files detected as BKDR_SIMBOT.SMAZ
*Note: Some component files may be hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.
To stop the malware/grayware from running when certain files are opened:
For Windows 2000, Windows XP, and Windows Server 2003:
- Right-click Start then click Search....
- In the Named input box, type the name of the file that was detected earlier.
- In the Look In drop-down list, select My Computer then press Enter.
- Once located, select the file then press SHIFT+DELETE to delete it.
For Windows Vista and Windows 7:
- Click Start>Computer.
- In the Search Computer input box, type the name of the file detected earlier, and press Enter.
- Once located, select the file then press SHIFT+DELETE to delete it.
*Note: Read the following Microsoft page if these steps do not work on Windows 7.
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_SIMBOT.SMAZ. 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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