Worm/Locksky.AB.1 - Worm

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Summary

Full description

Statistics

Virus:	Worm/Locksky.AB.1
Date discovered:	17/01/2006
Type:	Worm
In the wild:	Yes
Reported Infections:	Low
Distribution Potential:	Medium
Damage Potential:	Medium
Static file:	Yes
File size:	29.076 Bytes
MD5 checksum:	3b4b68e47b1515f5296004be07411a2f
VDF version:	6.33.00.132

General Method of propagation:
   • Email

Aliases:
   • Symantec: W32.Looksky.H@mm
   • Mcafee: W32/Loosky.dr
   • Kaspersky: Email-Worm.Win32.Locksky.ab
   • TrendMicro: WORM_LOCKSKY.AM
   • Sophos: W32/Loosky-AW
   • VirusBuster: I-Worm.Locksky.AS
   • Eset: Win32/Locksky.AI
   • Bitdefender: Win32.Locksky.AB@mm

Platforms / OS:
   • Windows 95
   • Windows 98
   • Windows 98 SE
   • Windows NT
   • Windows ME
   • Windows 2000
   • Windows XP
   • Windows 2003

Side effects:
   • Drops malicious files
   • Records keystrokes
   • Registry modification
   • Steals information
   • Third party control

Files It copies itself to the following locations:
   • %WINDIR%\sachostx.exe
   • %malware execution directory%\temp.bak

It deletes the following file:
   • %SYSDIR%\hard.lck

The following files are created:

– %SYSDIR%\msvcrl.dll Further investigation pointed out that this file is malware, too. Detected as: Worm/Locksky.P.9

– %SYSDIR%\sachostp.exe Furthermore it gets executed after it was fully created. Further investigation pointed out that this file is malware, too. Detected as: Worm/Locksky.V.1.B

– %SYSDIR%\sachostc.exe Furthermore it gets executed after it was fully created. Further investigation pointed out that this file is malware, too. Detected as: BDS/Locksky.K

– %SYSDIR%\sachostw.exe Furthermore it gets executed after it was fully created. Further investigation pointed out that this file is malware, too. Detected as: Worm/Locksky.T.6

– %SYSDIR%\sachosts.exe Furthermore it gets executed after it was fully created. Further investigation pointed out that this file is malware, too. Detected as: Worm/Locksky.V.1.C

It tries to download a file:

– The locations are the following:
   • http://proxy4u.ws:8080/**********
   • http://proxy4u.ws:8080/**********
   • http://usproxy2u.ws:8080/**********
   • http://usproxy2u.ws:8080/**********
At the time of writing this file was not online for further investigation.

Registry The following registry key is added in order to run the process after reboot:

– HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   • "HostSrv" = "%WINDIR%\sachostx.exe"

It creates the following entry in order to bypass the Windows XP firewall:

– HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\
   FirewallPolicy\StandardProfile\AuthorizedApplications\List
   • "%malware execution directory%\%executed file% "="%malware execution directory%\ %executed file% :*:Enabled:enable"
   • "%SYSDIR%\sachostw.exe"="%SYSDIR%\sachostw.exe:*:Enabled:enable"
   • "%SYSDIR%\sachostc.exe"="%SYSDIR%\sachostc.exe:*:Enabled:enable"
   • "%SYSDIR%\sachosts.exe"="%SYSDIR%\sachosts.exe:*:Enabled:enable"

Email It contains an integrated SMTP engine in order to send emails. A direct connection with the destination server will be established. The characteristics are described in the following:

From:
The sender address is spoofed.

To:
– Email addresses found in specific files on the system.
– Email addresses gathered from WAB (Windows Address Book)

Subject:
The following:
   • Your mail Account is Suspended

Body:
The body of the email is the following:

   • We regret to inform you that your account has been suspended due to the violation of our site policy, more info is attached.

Attachment:
The filename of the attachment is one of the following:
   • acc_info9.exe
   • ebay_info.exe
   • acc_inf19.exe

The attachment is a copy of the malware itself.

Mailing Search addresses:
It searches the following file for email addresses:
• htm

Backdoor The following ports are opened:

– %SYSDIR%\sachosts.exe on a random TCP port in order to provide an HTTP server.
– %SYSDIR%\sachostc.exe on a random TCP port in order to provide a proxy server.

Contact server:
The following:
   • http://proxy4u.ws/index.php?

As a result it may send some information.

Sends information about:
    • IP address
    • Current malware status
    • Opened port

Injection – It injects the following file into a process: %SYSDIR%\msvcrl.dll

Process name:
• %all running processes%

File details Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with the following runtime packer:
• UPX

See a brief description here.

Description inserted by Irina Boldea on Tue, 16 May 2006 14:19 (GMT+1)
Description updated by Irina Boldea on Tue, 16 May 2006 14:23 (GMT+1)

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