Security researchers at Symantec say the Blackshades malware is on the rise again roughly a year after the arrest of a key player associated with the program.
A remote access tool (RAT) used by hackers, Blackshades has been sold on underground forums since 2010, when its source code was leaked on the Internet. In 2012, an arrest was made. But use of the RAT has gone on, with an uptick occurring in the last five months. Once installed, Blackshades steals passwords and credentials from infected systems and sends them back to the attacker’s command-and-control (C&C) server.
“This increase in activity prompted us to investigate the main C&C servers that manage the latest infections,” blogged Santiago Cortes of Symantec’s Security Response Team. “Upon investigation, we found a connection to the Cool Exploit Kit, which has been used to distribute W32.Shadesrat, but also several other malware families.”
When researchers observed the increase in Blackshades (detected as W32.Shadesrat) infections, Symantec identified hundreds of C&C servers being used to steal credentials from compromised computers.
“W32.Shadesrat targets a wide variety of credentials including email services, Web services, instant messaging applications, and FTP clients,” Cortes blogged. “Spammers looking for new mail credentials, attackers trying to continue their security breaches with access to new servers and services, and attackers looking for specific information to exfiltrate might be interested in this kind of information.”
Nearly all of the C&C servers have hosted exploit kits at some point. Since the arrest of the author of the Blackhole and Cool Exploit kits, Neutrino has been the kit of choice, according to Symantec. The servers are also used to spread other malware such as Ransomlock and ZeroAccess.
“Once an unsuspecting user has been compromised, multiple payloads are downloaded and used to retain control by using Remote Administration Tools or downloaders that enable them to install additional malware with new functionalities,” Cortes blogged.
The distribution of the malware suggests that the attackers attempted to infect as many people as possible, and there are not aiming at specific people or targets.
“Lithuania and the United States host the highest amount of C&C servers,” noted Cortes. “India is the most affected country, followed by the United States and the United Kingdom, but countries all around the world have been affected by W32.Shadesrat.”