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Trojan:W32/Qhost.JE


First posted on 16 May 2007.
Source: SecurityHome

Aliases :

Trojan:W32/Qhost.JE is also known as Trojan.Win32.Qhost.je.

Explanation :

Trojan:W32/Qhost.JE is a trojan that steals sensitive information. It also modifies the hosts file in an attempt to redirect online bank traffic to a web site in Russia. The trojan has rootkit functionality.

Qhost.JE consists of multiple components. Its main component is named system32.exe. It sets a registry launchpoint for crypt32net.dll (detected as Trojan.Win32.Zapchast.co), loads a kernel.dll (Trojan.Win32.Delf.xi), and runs scardrv.exe (Trojan-Downloader.Win32.Small.djr).

When system32.exe is run it registers crypt32net.dll as a Winlogon notify library thus creating an autorun for itself. Basically the exported "ChainWlxLogoffEvent" function is run at every logon and it, in turn, runs system32.exe.

System32.exe creates these keys:


It sets these values:


Qhost.JE has rootkit functionality: kernel.dll sets a global windows hook and uses it to hide the malware processes. It does this by placing an inline hook on NtQuerySystemInformation(). The trojan also hooks HttpSendRequestA() from wininet.dll. A mutex called "ProcHideHook" is present when hooks are active.

Kernel.dll monitors HTTP request with the hook on HttpSendRequestA(). It grabs POST data from web traffic and sends it to a hidden window called "Windows System Messenger" maintained by system32.exe process. System32.exe writes data to a log when it receives the message.

The malware captures e-mail client passwords, clipboard data, and other information and writes them to C:WINDOWS mp.log. The trojan tries to upload this information to an FTP server. FTP username and password are hard-coded in the trojan.

Scardrv.exe is a SOCKS proxy listening on 18191. It also downloads a file from a web server, 84.252.148.70. The downloaded file is stored as "%WINDOWS%1.tmp". The download page was inaccessible at the time of analysis. System32.exe adds both itself and scardrv.exe to the Windows Firewall list of programs allowed to access the Internet.

System32.exe overwrites the hosts-file (%WINDOWS%system32driversetchosts). This is done in order to perform a so-called "pharming" attack i.e. an attack where the user is redirected onto a fraudulent site. Several online banking sites are redirected to a web server in Russia. Also, a number of sites of antivirus vendors are redirected to the localhost address in an attempt to prevent antivirus updates and web access to virus information. Some advertisement sites are also redirected to the localhost address.

List of banking sites redirected:


List of sites redirected to localhost address:

Last update 16 May 2007

 

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