RTKT_ZACESS.SM7
TrojanDropper:Win32/Sirefef.B (Microsoft); Rootkit.Win32.ZAccess.e (Kaspersky); Trojan.Zeroaccess!inf (Symantec)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This is Trend Micro's detection for ZeroAccess rootkit component. Once running, it checks if its service name starts with '.', if not, it will not continue. It then searches for a certain registry and deletes it. This rootkit monitors IRP Packet to prevent any application that accesses the malware such as forensic tools and security software from executing. It also modifies the Access Control List (ACL) of its component files to remove user's control for the files.
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 does not have any propagation routine.
It does not have any backdoor routine.
It does not drop any other file.
It does not have any downloading capability.
It does not have any information-stealing capability.
TECHNICAL DETAILS
Varies
SYS
Yes
16 Sep 2011
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.
Autostart Technique
This Trojan registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\{Malware File Name without Extension}
ImagePath = "%System%\DRIVERS\{Malware File Name}.sys"
Propagation
This Trojan does not have any propagation routine.
Backdoor Routine
This Trojan does not have any backdoor routine.
Dropping Routine
This Trojan does not drop any other file.
Download Routine
This Trojan does not have any downloading capability.
Information Theft
This Trojan does not have any information-stealing capability.
NOTES:
This is usually dropped by its main component as the following:
- %System%\DRIVERS\{Malware File Name}.sys
This is Trend Micro's detection for ZeroAccess rootkit component. Once running, it checks if its service name starts with '.', if not, it will not continue. It then searches for the registry below and deletes it:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\root\LEGACY_{service name}
This rootkit monitors IRP Packet to prevent any application that accesses the malware such as forensic tools and security software from executing. It also modifies the Access Control List (ACL) of its component files to remove user's control for the files.
This malware does not exploit any vulnerability.
SOLUTION
9.200
8.458.05
27 Sep 2011
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
Scan your computer with your Trend Micro product and note files detected as RTKT_ZACESS.SM7
Step 3
Restart in Safe Mode
Step 4
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\System\CurrentControlSet\Services
- {Malware File Name without Extension}
- {Malware File Name without Extension}
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as RTKT_ZACESS.SM7. 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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