[ISN] New Bagle, MyDoom variants roil Internet
isn at c4i.org
Wed Jul 21 09:49:22 EDT 2004
By Paul Roberts
IDG News Service
New versions of the Bagle and MyDoom worms surfaced on the Internet
Monday, and appear to be spreading.
Bagle.AI and MyDoom.N are both so-called "mass mailing" worms that use
a built-in SMTP engine that sends e-mail messages carrying
worm-infected file attachments from computer to computer on the
Internet, both using faked (or "spoofed") sender addresses, anti-virus
The new worm variants are just the latest in a string of virus
releases in recent days that have anti-virus software companies
scrambling to keep their customers protected.
W32.Bagle.AI first appeared Monday and is rated a "medium" threat by
McAfee's Antivirus Research Team, citing reports of the virus from
customers. McAfee rated MyDoom.N a "low" threat, whereas Computer
Associates noted the prevalence and destructiveness of the worm.
Similar to earlier versions of Bagle, the AI variant spreads through
shared file folders and in e-mail messages carrying the worm file as
an attachment, according to advisories from Sophos PLC and McAfee.
E-mail messages generated by the worm used forged (or "spoofed")
sender addresses and the subject line "Re:" Worm-infected file
attachments might be in ZIP, EXE, SCR, COM or CPL and also have
nonspecific names like "Moreinfo," "Details" or "Readme," anti-virus
Infected file attachments use one of a short list of names including
"MP3," "Doll" and "Cat."
The worm can also send copies of itself as a password-protected
compressed file with a ZIP extension. The password needed to unzip the
ZIP file is contained in a second file with a TXT, INI, DOC or other
extensions, McAfee said.
The MyDoom.N worm uses spoofed sender addresses such as "postmaster,"
"Post Office" and "MAILER-DAEMON" that make the e-mail resemble a
MyDoom.N messages also have nondescript Subject lines such as "hello,"
"hi" and "delivery failed." Virus file attachments have names like
"readme," "mail," "text" and "attachment." File extensions include
CMD, BAT, COM, EXE and ZIP, McAfee said.
Anti-virus companies issued updated virus definitions that can detect
the new Bagle and MyDoom variants and recommended that customers
update their anti-virus software.
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