F-Secure Virus Descriptions : I-Worm.Atak.a

[Summary] | [Detailed Description] | [Detection]

NAME:

I-Worm.Atak.a

Summary

A new simple massmailer was found on Monday 12th of July. It will attempt to spread on emails with an empty subject or one such as "Read the Result!", "Important Data!". It tries to disguise the original attachment extension by adding a large number of spaces after the beginning of the filename.

Detailed Description

The worm will create a mutex named "SloperMtx" to avoid running more than once simultaneously.

It will copy itself to:

 %SysDir%\hint.exe

Where %SysDir% is the local Windows System folder. First the worm attempts to create the file and then deletes it, finally copying itself to such location.

It will add an entry to the win.ini file using the Windows API call WritePrivateProfileStringA from the Kernel32.dll. The entry will have the form:

 [windows]
 load="%SysDir%\hint.exe"

Which will make Windows execute the worm on startup.

Afterwards it attempts to detect whether a debugger is loaded, aiming at avoiding being inspected by advanced users. It does so by calling the function IsDebuggerPresent from Kernel32.dll. The worm loads such DLL function itself, by means of Window's API LoadLiraryA.

Another trivial attempt of difficulting the analysis is when checking for Internet connection availability. It does so by loading a DLL, namely "wininet.dll", composing its name from parts "wini", "net." and "dll" at runtime. This a very basic and old "technique". Once it loads the DLL it will call its function, InternetGetConnectedState, to determine whether an Internet connection is available. If it's not so, it will wait, hoping the infected computer eventually goes online.

The following string is contained within the worm's body:

 -={ 4tt4(k 4g4!n$t N3tSky, B34gl3, MyD00m, L0vG4t3, N4ch!, Bl4st3r }=-

Email spreading

The messages will have any of the following subjects, or no subject at all:

 Read the Result!
 Important Data!

The attachment will have a random name and extension ".gif" or ".jpg" followed by white spaces and finally ending with ".exe" or ".zip".

The worm will collect e-mail address from files with extensions:

 .wab
 .adb
 .tbb
 .html
 .xml
 .cfg
 .vbs
 .msg
 .dbx
 .uin
 .jsp
 .asp
 .cgi
 .php
 .sht
 .mht
 .ods
 .log
 .htm
 .mbx
 .nch
 .eml
 .txt

The worm has its own SMTP engine which will use to deliver the infected emails.

Back to the Top

Detection

F-Secure Anti-Virus detects Atak.a with the following update:

[FSAV_Database_Version]

Version=2004-07-12_03

Back to the Top

Technical Details: Ero Carrera, July 16th, 2004;

F-Secure Corporation