Trend Micro Virus Alert - WORM_MYTOB.BI

As of May 31, 2005 9:11 AM PDT (Pacific Daylight Time), TrendLabs has declared a Medium Risk Virus Alert to control the spread of WORM_MYTOB.BI. TrendLabs has received several infection reports indicating that this malware is spreading in Belgium, Japan, Korea, India, United States, United Kingdom, and Germany.

Similar to other MYTOB variants, this memory-resident worm propagates by sending a copy of itself as an attachment (file size is around 29,868 to 29,882 bytes) to an email message, which it sends to target recipients using its own Simple Mail Transfer Protocol (SMTP) engine. Upon execution, it drops a copy of itself using the file name LIEN VAN DE KELDERRR.EXE in the Windows system folder.

The email message it sends has the following details:

Subject: (any of the following)

- {Random}
- *DETECTED* Online User Violation
- *IMPORTANT* Please Validate Your Email Account
- *IMPORTANT* Your Account Has Been Locked
- *WARNING* Your Email Account Will Be Closed
- Account Alert
- Email Account Suspension
- Important Notification
- Notice of account limitation
- Notice: **Last Warning**
- Notice:***Your email account will be suspended***
- Security measures
- Your email account access is restricted
- Your Email Account is Suspended For Security Reasons

Message body: (any of the following)

- Once you have completed the form in the attached file , your account records will not be interrupted and will continue as normal.
- please look at attached document.
- Please read the attached document and follow it's instructions.
- Please see the attachement.
- The original message has been included as an attachment.
- To safeguard your email account from possible termination, please see the attached file.
- To unblock your email account acces, please see the attachement.
- We attached some important information regarding your account.
- We have suspended some of your email services, to resolve the problem you should read the attached document.
- We regret to inform you that your account has been suspended due to the violation of our site policy, more info is attached.

Attachment: (any combination of the following file names and extensions)

File name:
- {random}
- account-details
- document
- document_full
- email-doc
- email-info
- info
- information
- info-text
- instructions
- your_details

Extension:
- BAT
- CMD
- EXE
- PIF
- SCR
- ZIP

It gathers target email addresses from the Temporary Internet Files folder, Windows address book (WAB), as well as from files with certain extension names. It may also generate email addresses by using a list of names and any of the domain names of the previously gathered addresses.

This worm also takes advantage of the LSASS vulnerability to propagate. For more information about the said vulnerability, please refer to the following Microsoft Web page:

http://www.microsoft.com/technet/security/bulletin/MS04-011.mspx

It opens a random port, allowing a remote user to access and perform malicious commands on affected machines. The said routine provides the remote user virtual control over affected systems, thus compromising system security.

Moreover, it prevents affected users from accessing several antivirus and security Web sites by redirecting the connection to the local machine. It also terminates several processes.

This worm also downloads a file, which Trend Micro detects as TSPY_AGENT.H. The downloaded file then drops an adware that Trend Micro detects as ADW_MEDTICKS.A.

It affects Windows 98, ME, NT, 2000, and XP.

TrendLabs will be releasing the following EPS deliverables:

TMCM Outbreak Prevention Policy 178 (Uploaded)
Control Pattern Release 2.650.05 (Uploaded)
Official Pattern Release 2.651.00 (ETA 1 hour)
Damage Cleanup Template 603.03 (Uploaded)
Official DCT 604 (ETA 1 hour 30 minutes)

For more information on WORM_MYTOB.BI, you can visit our Web site at:
http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM_MYTOB.BI