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Win32.MyDoom.F@mm

First posted on 21 November 2011.
Source: BitDefender

Aliases :

There are no other names known for Win32.MyDoom.F@mm.

Explanation :

This mass-mailer was written in Visual C++ 7 and packed with UPX 1.24.

It arrives in an email in the following format:

From: [forged email address]
Subject: with a 8% chance the subject line consists of 3 to 17 random letters; otherwise (92% chance) it is one of the following:
test
hi
hello
Returned Mail
Confirmation Required
Confirmation
Registration Confirmation
please reply
please read
Read this message
Readme
Important
Your account has expired
Expired account
Notification
automatic responder
automatic notification
You have 1 day left
Warning
Information
For your information
For you
Something for you
Read it immediately
Read this
Read it immediately!
Your credit card
Schedule
Accident
Attention
stolen
news
recent news
Wanted
fake
unknown
bug
forget
read now!
Current Status
Your request is being processed
Your order is being processed
Your request was registered
Your order was registered
Re: (censored)
Undeliverable message
Love is...
Love is
Your account is about to be expired
Your IP was logged
You use illegal file sharing...
Thank You very much
hi, it's me
Approved
Re: Approved
Details
Re: Details
Thank you
Re: Thank you
Announcement
(sometimes - 60% chance - the first letter of the above texts is capitalized; or - 10% chance - the entire subject line is capitalized).

Body: One of the following:
test
Details are in the attached document. You need Microsoft Office to open it.
See the attached file for details
Please see the attached file for details
The document was sent in compressed format.
Check the attached document.
Everything ok?
OK
Okay
I'm waiting
Read the details.
Here is the document.
I wait for your reply.
Is that from you?
Is that yours?
You are a bad writer
I have your password :)
Something about you
Kill the writer of this document!
We have received this document from your e-mail.
Here it is
See you
Greetings
Information about you
Please, reply
Reply
Take it
You are bad

Attachment: One of the following:
- [name].exe file (13% chance);
- [name].zip file (34.8% chance);
- [name].{txt, doc, htm, rtf, xls, jpg, gif, png}[40 to 159 spaces].{pif, scr, exe} (52.2% chance).
In 12% of cases, [name] is made up of 3 to 7 random characters; in the other 88% of cases, it is one of the following:
msg
doc
document
readme
text
file
data
test
message
body
details
creditcard
attachment
stuff
me
post
posting
textfile
info
information
note
notes
product
bill
check
ps
money
about
story
mail
list
joke
jokes
friend
site
website
object
mail2
part1
part4
part2
part3
misc
disc
paypal
approved
details
your_document
image
resume
photo

When first run, it creates HKLM/HKCU_ SoftwareMicrosoftWindowsCurrentVersionShell; this will be checked to see if the virus is already installed; a thread is created; in 70% of cases, this thread displays one of the following messages:

File is corrupted.

File cannot be opened.

Unable to open specified file.

In the other 30% of cases, it creates a temporary file named "Mail", "Body", "Text" or "Data", fills it with random rows of text and opens it with Notepad; when the user closes Notepad, the temporary file is deleted.

A mutex called "jmydoat[computer name]mtx" is used to avoid running multiple copies of the virus.

It drops and executes a DLL with a name of 4 to 8 random letters in the system folder (or in the folder for temporary files). This DLL has the following functionality:

- on Win9x systems, calls the RegisterServiceProcess function to hide the process;

- opens a backdoor server on port 1080; a connecting user can send an executable file that the backdoor will save and run; she can also order the infected machine to connect to a specified host and port and await commands on that connection;

- terminates processes that contain the following substrings in the name: "reged", "taskmo", "taskmg", "avp.", "avp32", "norton", "navapw", "navw3", "intrena", "mcafe".

The virus copies itself in the system folder (or the temporary folder) with a name of 4 to 13 random letters (with ".exe" extension); it appends a maximum of 8096 random bytes at the end of the file (offset 26000) so that the copy is not identical to the original version. An entry with a random name of 4 to 8 letters in the HKLM/HKCUSoftwareMicrosoftWindowsCurrentVersionRun key is created and pointed to the copy of the virus in the system/temp folder; this way, the virus will be run at start-up.

If the day of the month is between 17 and 22 and the computer is connected to the Internet, the virus creates a thread that will flood www.riaa.com (or riaa.com) in 33% of cases or www.microsoft.com (or microsoft.com) in 67% of cases. 64 threads are used to connect to the flooded website; after the main thread ends the connection with the flooded site, it waits for 1 minute and then loops (recreates 63 more connecting threads and reconnects itself).

The virus manages a list of email addresses that are gathered from the user's files; a thread monitors this list and sends email to the addresses in the lists, while the main thread adds addresses to the list by scanning the files.

The following files and folders are scanned:

- file c:init;
- Windows Address Book (WAB);
- Temporary Internet Files folder (5 levels of depth);
- fixed drives and ramdisks (15 levels of depth);
- all drives (5 levels of depth).

The following files are scanned for email addresses: files matching the masks: *., *.htm*, *.sht*, *.php*, *.asp* , *.dbx*, *.adb*, *.eml*, *.pl, *.msg*, *.vbs*, *.mht*, *.uin*, *.rtf*, *.ods*, *.mmf*, *.ncx*, *.mbx* with a maximum size of 204800 bytes; files *.txt with a maximum size of 81920 bytes; files *.tbb* files (The Bat! email archives) with a maximum size of 1228800 bytes; *.wab* files (Windows Address Book files) with a maximum size of 8388608 bytes; files matching the mask *inbox*.

Email addresses containing the following substrings will be avoided: avp, syma, icrosof, msn., hotmail, panda, sopho, borlan, inpris, example, mydoma, nodoma, ruslis, .gov, gov., .mil, foo., suppo, essagela, nai.co, isi.e, isc.o, secur, .acketst, pgp, ibm.com, google, kernel, linux, fido, usenet, sourcef, slashdot, sun.com, sgi.com, solaris, irix, iana, ietf, rfc-ed, sendmail, arin., ripe., berkeley, unix, math, bsd, mit.e, gnu, fsf., tanford.e, utgers.ed, mozilla, spam, admin, support, ntivi, listserv, certific, accoun, contact, master; email addresses beginning with spm, www, secur, abus, root, info, samples, noone, nobody, nothing, anyone, someone, your, you, me, bugs, rating, site no, somebody, privacy, service, help, not, submit, feste, ca, gold-certs, the.bat will also be avoided.

Files matching the following masks have a chance of being deleted when found: *.mdb* (98% chance), *.doc* (40%), *.xls* (60%), *.sav* (95%), *.jpg* (89%), *.avi* (10%), *.bmp* (15%).

In 40% of cases, or if the pathname of the folder that is scanned contains "shar" or "startup", or if it contains "start" and with a chance of 20%, the virus creates a zipped (75% chance) or plain (25% chance) copy of itself in that folder; the name of the copy contains 4 to 13 random letters and the ".zip" or ".exe" extension.

The virus will wait for approx. 32 seconds before restarting the scanning sequence.

The thread that sends email checks to see if the machine is connected to the Internet; it makes sure the list of target email addresses doesn't exceed 4096 entries; if there are more than 3 entries in the list, after 12 seconds of inactivity it will add a random email address to the list: {john, alex, james, sam, jim, smith, bill, jerry}@[domain of another address in the list].

The virus uses internal SMTP functions to send emails. It attempts to DNS-resolve the domain-part of the email address and use that host as an SMTP server; if it fails, it uses the user's configured SMTP server.

The thread that sends emails will pick a random entry in the list of target addresses, compose an email in the format described above and send it; another entry in the addresses list (or the address [3 to 5 random letters]@{aol.com, msn.com, yahoo.com, hotmail.com}, in 18% of cases) is used to forge the sender's address.

Last update 21 November 2011

 

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