BKDR_DELF.CE
Backdoor:Win32/Aphexdoor.10 (Microsoft); BackDoor-AIX (McAfee); Backdoor.Aphexdoor (Symantec); Backdoor.Win32.Aphexdoor.10 (Kaspersky); Trojan.Win32.Ircbot!cobra (v) (Sunbelt); Backdoor.Aphexdoor.1.0 (FSecure)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Backdoor
Destructiveness: No
Encrypted:
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.
TECHNICAL DETAILS
26,112 bytes
EXE
Yes
18 May 2012
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:
- %Windows%\winsock2.exe
(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
winsock2 = "%Windows%\winsock2.exe"
Other System Modifications
This backdoor deletes the following files:
- %Windows%\winsock2.exe
(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
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 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\Windows\CurrentVersion\Run
- winsock2 = "%Windows%\winsock2.exe"
Step 4
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_DELF.CE. 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 5
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %Windows%\winsock2.exe
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