BKDR_XYSYL.EVL
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Spammed via email, Downloaded from the Internet, Dropped by other malware
This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It 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
TCP port 8000 (iRDMI)
72,704 bytes
EXE
Yes
05 May 2012
Arrival Details
This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
It 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:
- %System Root%\Documents and Settings\All Users\svchost.exe
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
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
SunJavaUpdateSched = "%System Root%\Documents and Settings\All Users\svchost.exe"
Other System Modifications
This backdoor creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile\AuthorizedApplications\
List
{malware path}\{malware name}.exe = "{malware path}\{malware name}.exe:*:Enabled:1"
Backdoor Routine
This backdoor opens the following port(s) where it listens for remote commands:
- 8000
NOTES:
The infected machine can be accessed by opening a remote command prompt, which an attacker can use.
SOLUTION
9.200
8.946.01
27 Apr 2012
8.947.00
28 Apr 2012
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
Identify and terminate files detected as BKDR_XYSYL.EVL
- 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
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
- SunJavaUpdateSched = "%System Root%\Documents and Settings\All Users\svchost.exe"
- SunJavaUpdateSched = "%System Root%\Documents and Settings\All Users\svchost.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile\AuthorizedApplications\List
- {malware path}\{malware name}.exe = "{malware path}\{malware name}.exe:*:Enabled:1"
- {malware path}\{malware name}.exe = "{malware path}\{malware name}.exe:*:Enabled:1"
Step 4
Scan your computer with your Trend Micro product to delete files detected as BKDR_XYSYL.EVL. 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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