Trojan.Downloader.JPUY is distributed as an executable program with the filename, 'hpupdate.exe' (SHA1:9a0386dc813407ae7073ed148161c65caf499874).
This filename is the same as a legitimate software update program for Hewlett-Packard printers, and is likely used to trick users into believing that the trojan-downloader is authentic.
If the malicious program is installed onto a machine, it creates a batch file and installs itself at the following location:
This ensures that the trojan-downloader is automatically launched at each system startup.
The trojan-downloader also checks for and, if necessary, creates a mutex object (straightforwardly named 'Mutex') to prevent re-infection of a machine that has already been infected by the same malware.
File download and upload
Once the trojan-downloader is installed and running on the machine, it attempts to contact a remote command and control server, report its status and download a file:
- w w w.musicfile[obfuscated]/doc/<17-digit-random-number>.html
If the file is successfully downloaded, the trojan-downloader then executes it on the machine.
The trojan-downloader is also able upload arbitrary files on the infected machine to its command and control server.
In the sample analyzed, the malware also harvested browsing history details from the web browser on the infected machine.