Resolve for Bdoor-CHR/W32/MyDoom

Resolve is the name for a set of small, downloadable Sophos utilities designed to remove and undo the changes made by certain viruses, Trojans and worms.

They terminate any virus processes and reset any registry keys that the virus changed. Existing infections can be cleaned up quickly and easily, both on individual workstations and over networks with large numbers of computers.

W32/MyDoom-A is a worm which spreads by email. When the infected attachment is launched, the worm harvests email addresses from address books and from files with the following extensions: WAB, TXT, HTM, SHT, PHP, ASP, DBX, TBB, ADB and PL.

W32/MyDoom-A creates a file called Message in the temp folder and runs Notepad to display the contents, which displays random characters.

W32/MyDoom-A 'spoofs', using randomly chosen email addresses in the "To:" and "From:" fields as well as a randomly chosen subject line. The emails distributing this worm have the following characteristics.

Subject lines error hello hi mail delivery system mail transaction failed server report status test [random collection of characters]

Message texts test The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment The message contains Unicode characters and has been sent as a binary attachment. Mail transaction failed. Partial message is available.

Attachment filenames body data doc document file message readme test [random collection of characters]

Attached files will have an extension of BAT, CMD, EXE, PIF, SCR or ZIP.

W32/MyDoom-A is programmed to not forward itself via email if the recipient email address satisfies various conditions:

The worm will not send itself to email addresses belonging to domains containing the following strings: acketst, arin., avp, berkeley, borlan, bsd, example, fido, foo., fsf., gnu, google, .gov, gov., hotmail, iana, ibm.com, icrosof, ietf, inpris, isc.o, isi.e, kernel, linux, math, .mil, mit.e, mozilla, msn., mydomai, nodomai, panda, pgp, rfc-ed, ripe., ruslis, secur, sendmail, sopho, syma, tanford.e, unix, usenet, utgers.ed As a consequence the worm does not forward itself to a number of email domains, including several anti-virus companies and Microsoft. The worm will not send itself to email addresses in which the username contains the following strings: abuse, anyone, bugs, ca, contact, feste, gold-certs, help, info, me, no, noone, nobody, not, nothing, page, postmaster, privacy, rating, root, samples, secur, service, site, spm, soft, somebody, someone, submit, the.bat, webmaster, you, your, www The worm will not send itself to email addresses which contain the the following strings: admin, accoun, bsd, certific, google, icrosoft, linux, listserv, ntivi, spam, support, unix

The worm can also copy itself into the shared folder of the KaZaA peer-to-peer application with one of the following filenames and a PIF, EXE, SCR or BAT extension: activation_crack icq2004-final nuke2004 office_crack rootkitXP strip-girl-2.0bdcom_patches winamp5

Further reading: MyDoom worm spreads widely across internet, Sophos warns users to be wary of viral email and hacker attack W32/MyDoom-A is a worm which spreads by email. When the infected attachment is launched, the worm harvests email addresses from address books and from files with the following extensions: WAB, TXT, HTM, SHT, PHP, ASP, DBX, TBB, ADB and PL.

W32/MyDoom-A creates a file called Message in the temp folder and runs Notepad to display the contents, which displays random characters.

W32/MyDoom-A 'spoofs', using randomly chosen email addresses in the "To:" and "From:" fields as well as a randomly chosen subject line. The emails distributing this worm have the following characteristics.

Subject lines error hello hi mail delivery system mail transaction failed server report status test [random collection of characters]

Message texts test The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment The message contains Unicode characters and has been sent as a binary attachment. Mail transaction failed. Partial message is available.

Attachment filenames body data doc document file message readme test [random collection of characters]

Attached files will have an extension of BAT, CMD, EXE, PIF, SCR or ZIP.

W32/MyDoom-A is programmed to not forward itself via email if the recipient email address satisfies various conditions:

The worm will not send itself to email addresses belonging to domains containing the following strings: acketst, arin., avp, berkeley, borlan, bsd, example, fido, foo., fsf., gnu, google, .gov, gov., hotmail, iana, ibm.com, icrosof, ietf, inpris, isc.o, isi.e, kernel, linux, math, .mil, mit.e, mozilla, msn., mydomai, nodomai, panda, pgp, rfc-ed, ripe., ruslis, secur, sendmail, sopho, syma, tanford.e, unix, usenet, utgers.ed As a consequence the worm does not forward itself to a number of email domains, including several anti-virus companies and Microsoft. The worm will not send itself to email addresses in which the username contains the following strings: abuse, anyone, bugs, ca, contact, feste, gold-certs, help, info, me, no, noone, nobody, not, nothing, page, postmaster, privacy, rating, root, samples, secur, service, site, spm, soft, somebody, someone, submit, the.bat, webmaster, you, your, www The worm will not send itself to email addresses which contain the the following strings: admin, accoun, bsd, certific, google, icrosoft, linux, listserv, ntivi, spam, support, unix

The worm can also copy itself into the shared folder of the KaZaA peer-to-peer application with one of the following filenames and a PIF, EXE, SCR or BAT extension: activation_crack icq2004-final nuke2004 office_crack rootkitXP strip-girl-2.0bdcom_patches winamp5

W32/MyDoom-A creates a file called taskmon.exe in the system or temp folder and adds the following registry entry to run this file every time Windows starts up:

HKLMSoftwareMicrosoftWindowsCurrentVersionRunTaskmon = taskmon.exe

Please note that on Windows 95/98/Me, there is a legitimate file called taskmon.exe in the Windows folder.

W32/MyDoom-A also drops a file named shimgapi.dll to the temp or system folder. This is a backdoor program loaded by the worm that allows outsiders to connect to TCP port 3127. The DLL adds the following registry entry so that it is run on startup:

HKCRCLSID{E6FB5E20-DE35-11CF-9C87-00AA005127ED}InProcServer32 Default= ""

The worm will also add the following entries to the registry:

HKLMSoftwareMicrosoftWindowsCurrentVersionExplorerComDlg32 HKCUSoftwareMicrosoftWindowsCurrentVersionExplorerComDlg32

W32/MyDoom-A, W32/MyDoom-AJ, W32/MyDoom-B, W32/MyDoom-F, W32/MyDoom-N, W32/MyDoom-O, W32/MyDoom-S and Troj/Bdoor-CHR can be removed from Windows computers automatically with the following Resolve tools:

BDLAAGUI is a disinfector for standalone Windows computers. To use it you have to do the following: ￭ Open MYDOOGUI.com file from your desktop after downloading it. ￭ Click on the Start Scan Button. ￭ Wait for the process to complete.

MYDOOSFX.EXE is a self-extracting archive containing MYDOOCLI, a Resolve command line disinfector for use on Windows networks. Read the notes enclosed in the self-extractor for details on running this program.

For Troj/Bdoor-CHR, you should replace the HOSTS file from backup, or open it in Notepad and remove any of the entries listed in the virus description.