Cybercriminals are increasingly using the "Blackshades" malware program whose source code was leaked three years ago, according to an analysis by Symantec.
Blackshades, which Symantec identifies as "W32.Shadesrat," has been infecting more Microsoft Windows computers and is being controlled by hundreds of command-and-control servers worldwide, which deliver instructions and receive information, wrote Santiago Cortes, a security response engineer at Symantec, in a blog post.
Blackshades is a remote access tool (RAT) that collects usernames and passwords for email and Web services, instant messaging applications, FTP clients and more. It has been sold on underground forums since at least 2010.
It's common for hackers to use remote access tools, which can be used to upload other malware to a computer or manipulate files. To avoid antivirus software, the programs are often frequently modified.
Lithuania and the U.S. have the highest number of command-and-control servers, Cortes wrote. Nearly all of those servers at one point have hosted exploit kits, a kind of booby trap that delivers malware to computers with software vulnerabilities.
India, the U.S. and the U.K. have the most computers infected with Blackshades, Cortes wrote.
"The distribution of the threats suggests that the attackers attempted to infect as many computers as possible," Cortes wrote. "The attackers do not seem to have targeted specific people or companies."
Earlier this year, Symantec wrote that a license to use Blackshades costs between US$40 to $100 a year.
Last year, Symantec wrote that Blackshades had been promoted on underground forums by a person going by the nickname "xVisceral."
In June 2012, the U.S. Attorney's Office for the Southern District of New York announced the arrest of Michael Hogue in Tucson, Arizona. It alleged he went by the xVisceral nickname and sold RATs. Hogue was arrested with 23 others in a "carding" scheme, which involved trafficking in financial details.
Hogue entered a plea in the case in January, but it did not appear from the court file that he had been sentenced yet. He was charged with conspiracy to commit computer hacking and distribution of malware.
Send news tips and comments to [email protected] Follow me on Twitter: @jeremy_kirk