Trojan-Downloader:W32/Exchanger.AJ

This malware is spread via spam emails with the title "CNN Alerts". These emails are crafted to resemble a real CNN news alert email.

The spam emails contain a link or links; in this case, the links are "Usher re-hires mother as manager" and "FULL STORY". When the user clicks these links, a prompt will appear requesting the user to download and execute a file named adobe_flash.exe, which is purported to be necessary to read the full story. The downloadable file is in fact malware. Once the file is downloaded and installed, it then starts as a service and will start on every subsequent system startup as well. On execution, the malware will make a copy of itself in the Window folders with the name %windir%\system32\ as CbEvtSvc.exe. The malware will then attempt to connect to a remote server and send information about the infected system. If this connection to the remote server is established, the malware may also be instructed to download and execute additional malware onto the infected system.

Registry Modifications

Sets these values:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\CbEvtSvc Type = 00000010 HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\CbEvtSvc Start = 00000002 HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\CbEvtSvc ErrorControl = 00000001 HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\CbEvtSvc ImagePath = %SystemRoot%\System32\CbEvtSvc.exe -k netsvcs HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\CbEvtSvc DisplayName = CbEvtSvc HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\CbEvtSvc\Security Security = \x01\x00\x14\x80... HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\CbEvtSvc ObjectName = LocalSystem