WORM_PRASH.B

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.

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.