TROJ_ALYAK.C
Trojan:Win32/Alyak.B (Microsoft); Trojan.Gen (Symantec); Trojan.Win32.Generic!BT (Sunbelt)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It deletes itself after execution.
TECHNICAL DETAILS
40,977 bytes
EXE
Yes
14 Sep 2012
Arrival Details
This Trojan 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 Trojan drops the following copies of itself into the affected system:
- %System%\AYLaunch.exe
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{7FBF9CDD-CF00-ABB4-5DC9-931176F0A978}
stubpath = "%SystemRoot%\system32\AYLaunch.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{7FBF9CDD-CF00-ABB4-5DC9-931176F0A978}
It deletes the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
Active Setup\Installed Components\{7FBF9CDD-CF00-ABB4-5DC9-931176F0A978}
Other Details
This Trojan connects to the following possibly malicious URL:
- http://blog.{BLOCKED}o.com/{random path}
- http://www.{BLOCKED}0.com/images/1.txt
- http://kglhk.{BLOCKED}55.com/2.txt
It deletes itself after execution.
This report is generated via an automated analysis system.
SOLUTION
9.200
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Restart in Safe Mode
Step 3
Delete this registry key
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\Active Setup\Installed Components
- {7FBF9CDD-CF00-ABB4-5DC9-931176F0A978}
Step 4
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\Active Setup\Installed Components\{7FBF9CDD-CF00-ABB4-5DC9-931176F0A978}
- stubpath = "%SystemRoot%\system32\AYLaunch.exe"
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_ALYAK.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.
Step 6
Restore these deleted registry keys/values from backup
*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- In HKEY_CURRENT_USER\Software\Microsoft\Active Setup\Installed Components
- {7FBF9CDD-CF00-ABB4-5DC9-931176F0A978}
Did this description help? Tell us how we did.