The HoT malware kit came on the underground Russian cybercrime market in late July, selling for $2,000, including free updates. The first iteration was touted to include form grabbers and backdoors, and claims to run on 15 different Linux distributions, including Ubuntu, Fedora, and Debian. But researchers at RSA's FraudAction team recently obtained and tested HoT binaries and its builder and found its features aren't so hot after all.
"Our research and analysis shows that, in reality, HoT's grabbing abilities are very limited, if not absent, which would make the malware a prototype that needs a lot more work before it can be considered a commercially viable banking Trojan," says Yotam Gottesman, senior security researcher for RSA FraudAction Research Labs.
The Trojan -- which has not yet been detected in any attacks at this time -- includes a builder, a Windows executable that allows a botmaster to generate new variants of the malware on-demand.
"In his sales adverts, Hand of Thief's developer explained that he is in the final stages of implementing the web-injection mechanism for the malware. Researching the Trojan proved that no injections are currently in place, but the preparation for such a mechanism is," Gottesman says in a blog post today about the research.
RSA tested the Trojan and found it could indeed inject itself into a browser process, but, in most cases, froze or crashed the browser. "When using Firefox on the infected machine, HoT captured only empty requests with no information being delivered to the drop server. When browsing with Google Chrome, HoT did manage to capture some requests and relay them to its server," Gottesman says.
But the Trojan had no way to filter information, so it would capture all requests from the browser in a generic manner, which would clog the drop server with "useless data," according to RSA.
RSA says HoT's developer doesn't offer a recommended method of infection besides email or social engineering tactics. But it does come with some anti-virtual machine functions to deter researchers, RSA found. It also employs packing to avoid detection. "Beyond using a packer and string obfuscation, it appears that HoT's developer invested in additional anti-research functions, one of which is Anti-Virtual Machines," Gottesman says.
The bottom line is HoT is more of a work in progress than a commercial tool as yet. "Although it initially appeared to be a compelling new Trojan entrant, RSA's in-depth analysis of the code proves it is a prototype more than true commercially viable malware, crashing the browsers on the infected machines and displaying overall inability to properly grab data," Gottesman says.
It's also easy to eradicate. "Furthermore, HoT can also be easily removed from the machine by deleting the files dropped during the HoT installation process," he says.
The full blog post, including screen shots, is available here.
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