BKDR_SERVU.JBR
Trojan:Win32/Orsam!rts (Microsoft), Server-FTP.Win32.Serv-U.gpr (Kaspersky)
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: Yes
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.
It listens on port(s). It executes commands from a remote malicious user, effectively compromising the affected system.
TECHNICAL DETAILS
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 component file(s):
- {malware path}\AvMeter32a.dll - contains the version and process ID of the backdoor
- {malware path}\pagefile.sys - contains the logs of the backdoor
Backdoor Routine
This backdoor listens on the following port(s):
- 43958
It executes the following commands from a remote malicious user:
- Allow anonymous access
- Execute programs
- Get information regarding the system
- List, delete, and create folders
- Send and receive messages
- Upload and download files
NOTES:
It is a modified ServU application that may be used as a remote access tool by a remote user. ServU is an FTP server. Using TCP port 43958, it waits for connections from a remote user.
It then allows a remote user to connect to the affected system and perform malicious commands, such as downloading files. The said routine compromises system security.
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
Identify and terminate files detected as BKDR_SERVU.JBR
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
Step 3
Search and delete these files
- {malware path}\AvMeter32a.dll
- {malware path}\pagefile.sys
Step 4
Scan your computer with your Trend Micro product to delete files detected as BKDR_SERVU.JBR. 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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