WORM_PRASH.B

 Modified by: Christopher Daniel So

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet

This worm attempts to get a list of previous connections from an infected machine. It then checks the port of the remote server where the infected machine tries to connect. If the port is 1433, it launches an SQL Server attack. If the port is 445, it launches a Server Message Block (SMB) attack. It also exploits certain vulnerabilities to download other malware to other systems in the remote server it is trying to attack.

This worm 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

File Size:

139,264 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Jun 2012

Payload:

Downloads files, Compromises system security

Arrival Details

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Download Routine

This worm connects to the following URL(s) to download its configuration file:

  • http://soft.{BLOCKED}4.info/history/list.asp - encrypted configuration file
  • http://{BLOCKED}s.into4.info/list.asp - encrypted configuration file
  • http://cc.{BLOCKED}4.info/geturl.asp - contains list of URLs

NOTES:

If this worm is running under Windows XP, it prevents DDOS by checking if the connection speed is greater than 128 Kbps. If the speed is greater than 128 Kbps, it terminates the process with the highest bandwidth consumption. It also terminates processes with more than 5 network connections.

It attempts to get a list of previous connections from an infected machine. It then checks the port of the remote server where the infected machine tries to connect. If the port is 1433, it launches an SQL Server attack. If the port is 445, it launches a Server Message Block (SMB) attack. It exploits the following vulnerabilities to download other malware to other computers in the remote server it is trying to attack:

  • (MS08-067) Vulnerability in Server Service Could Allow Remote Code Execution (958644)
  • Microsoft SQL Server 'sa' Login With 'Null' Password Vulnerability

It makes the targetted computer access the following FTP sites to download files:

  • ftp://{BLOCKED}i.in.into4.info
  • ftp://to.{BLOCKED}a.com

As of this writing, the following files are downloaded:

  • A08.exe - detected by Trend Micro as BKDR_RBOT.SMB
  • B08.exe
  • C001.exe - detected by Trend Micro as TROJ_AGENT.AZD
  • G001.exe
  • J001.exe

It then executes the downloaded files. As a result, routines of the downloaded files are exhibited on the affected system. Note that the downloaded files could change anytime.

This malware is typically installed as a service.

  SOLUTION

Minimum Scan Engine:

9.200

VSAPI OPR PATTERN File:

9.163.00

VSAPI OPR PATTERN Date:

03 Jun 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

Remove malware files dropped/downloaded by WORM_PRASH.B

Step 3

Scan your computer with your Trend Micro product and note files detected as WORM_PRASH.B

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Search and delete the file detected as WORM_PRASH.B

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files in the search result.

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_PRASH.B. 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 7

Download and apply these security patches Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.


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