North Korean official news agency site serves malware
A security researcher found that the site hosts a malicious file called FlashPlayer10.zip that is served by JavaScript code loaded from kcna.user.exploit.exploit.kcmsf (kcmsf is a custom file extension used by the site).
FlashPlayer10.zip contains two executable files called "Install Flash Player 10 Activex.exe" and "Install Flash Player 10 Plugin.exe." Both of the files are malicious, according to scans done with VirusTotal, an online file scanning service that uses multiple antivirus engines, said the researcher, who uses the online alias InfoSecOtter, in a blog post Sunday.
Security researchers from antivirus firm Bitdefender independently confirmed Tuesday that the files are malicious after obtaining the ZIP archive themselves from kcna.kp, the site of the Korean Central News Agency.
A quick look at the executable files suggests that the malware might steal passwords from browsers, said Bogdan Botezatu, a senior e-threat analyst at Bitdefender. It might also do other things, but more time is required to perform a thorough analysis.
One of the files was already in the VirusTotal database since October 2013, but they might be much older. The timestamp on the files in the ZIP archive suggests they were created in December 2012.
This means the attempt to infect users through the site most likely predates the attack against Sony Pictures in December that the FBI attributed to North Korea.
It's also not clear when the site serves the FlashPlayer10.zip file, as not all users are prompted to download it. The JavaScript code that triggers the download might check for special conditions like the user system's browser version, OS, language preference, location, or other attributes. That mechanism has not yet been researched.
There are also multiple references to the word exploit in different files and directories on the site, as well as code that appears to dynamically generate PDF file names for download.
Since many aspects of this attack are still uncertain, like whether the site contains other exploits in addition to the malware that masquerades as Flash Player, users who visited the site should err on the side of caution and scan their computers for malware and take security precautions if visiting the site in the future.