BKDR_FEXEL.W
Backdoor.Fexel (Norton)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Threat Type: Backdoor
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Dropped by other malware, Downloaded from the Internet
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 is a component of other malware.
It does not have any propagation routine.
It executes commands from a remote malicious user, effectively compromising the affected system.
TECHNICAL DETAILS
116,224 bytes
DLL
Yes
14 May 2014
Compromises system security, Connects to URLs/IPs
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 adds the following mutexes to ensure that only one of its copies runs at any one time:
- GDGSYDLYR_-{random numbers}
It is a component of other malware.
Propagation
This backdoor does not have any propagation routine.
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- File Management (Create, Delete, Move)
- Downloads & Execute Files
- Terminate Processes
- Execute Command Shell
- Uninstall Itself in the Affected Machine
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- {BLOCKED}.{BLOCKED}.238.178:443/search?hl={random}
NOTES:
It sends the following information to the URL upon connection:
- OS Version
- Volume Information
- Computer Name
- Current User Name
It saves the file it downloads as %User Temp%\{random}d.dat as one of its backdoor routines.
It does not have rootkit capabilities.
It does not exploit any vulnerability.
SOLUTION
9.700
10.794.04
14 May 2014
10.795.00
15 May 2014
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
Scan your computer with your Trend Micro product and note files detected as BKDR_FEXEL.W
Step 3
Restart in Safe Mode
Step 4
Search and delete files detected as BKDR_FEXEL.W
Step 5
Search and delete these files
- %User Temp%\{random}d.dat
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_FEXEL.W. 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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