Worm_Mytob.AB, like other WORM_MYTOB variants, propagates by sending a copy of itself as an attachment to an email message, which it sends to target recipients using its own Simple Mail Transfer Protocol (SMTP) engine. The email it sends out has the following details:
Subject: (any of the following)
(random)
Error
Good day
hello
Mail Delivery System
Mail Transaction Failed
Server Report
Status
Message body: (any of the following)
Mail transaction failed. Partial message is available.
The message contains Unicode characters and has been sent as a binary attachment.
The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment.
The original message was included as an attachment.
I have received your document. The corrected document is attached.
Attachment: (any of the following file names)
(random)
body
data
doc
document
file
message
readme
test
text
(with any of the following extensions)
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 following Windows vulnerabilities to propagate:
RPC/DCOM vulnerability
LSASS vulnerability
For more information about these vulnerabilities, please refer to the following Microsoft Web pages:
Microsoft Security Bulletin MS03-026
Microsoft Security Bulletin MS04-011
This worm has backdoor capabilities, which allow a remote user to perform malicious commands on the affected machine. The said routine provides remote users virtual control over affected systems, thus compromising system security.
Moreover, it prevents users from accessing several antivirus and security Web sites by redirecting the connection to the local machine. It also drops other malicious files, which is detected by Trend Micro as TROJ_ROOTDROP.A, TROJ_ROOTKIT.H, WORM_MYTOB.Q.
Technical details can be found at Trend Micro page.
4/8: Mytob-AB Worm Comes as Attachment
