Name :	Trojan-Downloader:W32/Agent.EOA
Size:	20,992
Category:	Malware
Type:	Trojan-Downloader
Platform:	W32

Trojan-Downloader:W32/Agent.EOA was initially associated with the recent PDF exploit Malware run (October 2007), detected as Exploit:W32/AdobeReader, Agent.EOA normally arrives as a dropped/downloaded Malware component by other Malware running on the infected system. The November 2007 and latest, the January 2008 reports however, now show that this Trojan is being spammed as an attachment to e-mails usually attempting to entice the user into opening a greeting card attachment. Upon execution, it drops/downloads and executes several other Trojans onto the system.

Depending on what system the OS version is, the Malware will overwrite any of the following files; with another Trojan embedded in its resource section:


This newly created Trojan is detected as Trojan-Downloader:W32/Agent.ACL / Trojan-Downloader:W32/Agent.hbm . It is then executed as a driver service using the Service Control Manager, thus further compromising the system.

The Malware will then drop yet another malicious file in the system as:


This new driver will then be loaded and executed using a native call to NtLoadDriver after adjusting necessary system privileges needed to perform such commands. This new sys file is detected by F-Secure products as Trojan-Downloader:W32/Agent.DPE.

Due to this action, the following registry associated with the Malware will be created:


Note: %system% refers to the default windows System directory; it is usually C:\Windows\System32.

The above registry becomes:


Lastly, using a hidden "browser" process (e.g. iexplore.exe, firefox.exe), it will inject another malware executable image in that process space to enable downloading of other malicious files into the user's system. Using this approach, it ensures that the downloader component will be able to do its job, since it is most likely that the computer's Internet browser is allowed to pass through the system's firewall.

The injected image, is then responsible for downloading other files from the remote servers and executing them on the compromised system. As at current testing, the download file is detected as one of the following: