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F-Secure Malware Information Pages: Gurong.A
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| Radar |
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Summary
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| The Gurong.A worm appeared on the 21st of March 2006. This worm spreads in e-mails and in Kazaa shared folders. It has a rootkit functionality. |
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Disinfection
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Detection and Disinfection of Rootkits
If the rootkit is not detected or it is hidden, in order that the FSAV cannot detect its file, it is still possible to detect the malicious activity by scanning the system with a generic rootkit scanner, such as F-Secure BlackLight. More information about F-Secure BlackLight Rootkit Elimination Technology can be found here:
http://www.f-secure.com/blacklight/
The BlackLight utility is also able to disinfect computers that are infected by rootkits. |
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Detailed Description
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Installation to system
After the worm's file is run, it copies itself to the Windows System folder as wmedia16.exe and creates a startup key value for this file in the Registry:
[HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
"WMedia16" = "%WinSysDir%\wmedia16.exe"
where "%WinSysDir% represents the Windows System folder.
Rootkit Hiding Techniques
The worm is able to hide the following items:
- Processes
- Files
- Registry keys and values
When the worm is active, it hides its own process, file and launch point in the registry.
The worm installs a call gate through \Device\PhysicalMemory to execute part of its code in kernel mode (ring 0). The kernel-mode code replaces the following function pointers from the system service table:
- NtClose
- NtCreateFile
- NtEnumerateKey
- NtEnumerateValueKey
- NtOpenFile
- NtQueryDirectoryFile
This allows it to hide files, registry keys and values. In addition, the worm is able to modify kernel-mode process structures to hide any process it specifies.
Spreading in e-mails
Before spreading, the worm looks for e-mail addresses in the victim's Windows Address Book (WAB) file and also in files with the following extensions:
- adb
- asp
- dbx
- htm
- php
- pl
- sht
- tbb
- txt
- wab
The worm ignores e-mail addresses that contains any of the following substrings:
- .aero
- .gov
- .mil
- accoun
- AccountRobot
- acketst
- admin
- alert
- anyone
- arin.
- avp
- berkeley
- borlan
- bsd
- bsd
- bugs
- ca
- certific
- contact
- example
- feste
- fethard
- fido
- foo.
- fraud
- fsf.
- gnu
- gold-certs
- google
- google
- gov.
- help
- hotmail
- iana
- ibm.com
- icrosof
- icrosoft
- ietf
- info
- inpris
- isc.o
- isi.e
- kernel
- linux
- linux
- listserv
- math
- me
- mit.e
- mozilla
- msn.
- mydomai
- no
- nobody
- nodomai
- noone
- not
- nothing
- ntivi
- page
- panda
- pgp
- postmaster
- privacy
- rating
- rfc-ed
- ripe.
- root
- ruslis
- samples
- secur
- sendmail
- service
- site
- soft
- somebody
- someone
- sopho
- submit
- support
- syma
- tanford.e
- the.bat
- unix
- unix
- usenet
- utgers.ed
- webmaster
- webmoney
- you
- your
The subject of an infected message can be one of the following:
- Greetings!
- Hello friend ;)
- Hey dear!
- Re: Hello
- Re: I got it! Try it now!
- Re[2]: wazzup bro
- Wazzap bro!!
The body text of an infected message can be one of the following:
- Greetings! Check out my portfolio, please! Here is some my photos in the archive.
- Greetings. Here is some my nude photos in the attachment.
- Hello bro! Here is my new girlfriend's photo! Check it out!
- Hello buddy! Take a look at attachment! Here is my nude 17-yr sister!
- Hello! Here is NEW smiles pack for MSN messenger! It is really cool ;)
- Hello! I sent you new skype plug-in, as you wished.
- Hello! There is NEW plug-in for MSN. Try it out!
- Hey bro! Check out attachment! There is a new plug-in for skype!
- Hey dear! Here is my photos, as I promised.
- Hey friend! Try this new smiles pack for MSN messenger!
- Hey man! Take a look at attachment!
- Whatz up man! There is my nude 17-yr sister in the attachment!'
The infected attachment name can be any of the following:
- body
- conf_data
- doc
- document
- i_love_u
- i_luv_u
- port_imgs
- sex_girls
- sex_pics
Infected attachments can have the following extensions:
The worm spoofs (fakes) the sender's e-mail address. The following user names are used to compose the fake sender's address:
- adam
- alex
- alexey
- alice
- andrew
- anna
- bob
- boris
- brenda
- brent
- brian
- claudia
- craig
- cyber
- dan
- dave
- david
- debby
- den
- dmitry
- frank
- george
- gerhard
- helen
- ilya
- james
- jane
- jayson
- jerry
- jim
- jimmy
- joe
- john
- jose
- julie
- kevin
- lee
- leo
- linda
- linda
- maria
- marina
- mary
- matt
- michael
- mike
- nikolay
- olga
- peter
- ray
- robert
- sam
- sandra
- serg
- smith
- steve
- tom
- vlad
- vladimir
The following domain names are used to compose the fake sender's address:
- aol.com
- earthlink.net
- hotmail.com
- msn.com
- yahoo.com
Spreading to Kazaa shared folders
The worm copies itself to Kazaa (peer-to-peer client) shared folder with the following names:
- 0day_patch
- dcom_patches
- icq5
- lsas_patches
- msblast_patches
- office_crack
- skype_video
- strip-girl4.0c
- trillian_crack_all
- winamp5
- xp_activation
The extensions of the copied files are randomly selected from the following variants:
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Detection
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F-Secure Anti-Virus detects this malware with the following updates: [FSAV_Database_Version] Version = 2006-03-21_03.
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F-Secure Corporation |
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Last Modified: March 23, 2006
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