A group has been singled out as the attacker behind the recently disclosed hack against Anthem, believed to be the largest waged against a health care company.
It was Black Vine that broke into the health insurer's systems and stole more than 80 million patients records, Symantec said Tuesday in a report.
For Black Vine, it was the latest in a long line of hacks that began in 2012. Black Vine has gone after other businesses that deal with sensitive and critical data, including organizations in the aerospace, technology and finance industries, according to Symantec. The majority of the attacks (82 percent) were waged against U.S. businesses.
Black Vine has deep pockets, giving the group the resources to customize malware, and uses zero-day vulnerabilities in Microsoft Internet Explorer to launch watering-hole attacks. The IE exploits were used to install malware that gave Black Vine remote access to a victim's computer. To evade detection, Black Vine frequently updates its malware, according to Symantec.
The three modified malware strains Black Vine uses are Sakurel and Hurix, which are detected as Backdoor.Mivast, and Mivast, which is detected as Trojan.Sakurel.
Symantec claimed some Black Vine members have ties to Topsec, a Chinese IT security company, and the group has access to the Edlerwood framework, a platform for distributing new zero-day vulnerabilities. During its research, Symantec discovered Black Vine began using exploits around the same time as other hacking groups. Each group delivered different malware and went after certain organizations, but the fact that they used the same exploit suggests the attackers relied on the same distribution network.
One of the group's first attacks came in December 2012 against gas turbine manufacturer Capstone Turbine, Symantec said. That hack used the IE exploit CVE-2012-4792 and delivered the Sakurel malware. Symantec noted that the malware was signed with a digital certificate attributed to a company called Micro Digital, fooling Windows into believing the program was legitimate.
That same month, another unnamed turbine power manufacturer was attacked using Sakurel, leading Symantec to believe Black Vine was going after businesses in the energy industry.
In 2013 and 2014, Black Vine targeted companies in the aviation and aerospace industries. One third-party blog cited by Symantec noted that in 2013 specific employees at a global airline were sent spear phishing emails containing a URL that instructed them to download Hurix.
Black Vine compromised the website of a European aerospace company in 2014, accessing the company's domain and using it to attack the site's visitors. To carry out this attack, Black Vine used the IE vulnerability CVE-2014-0322 and installed an updated version of Sakurel on a victim's computer.
The Black Vine malware Mivast was used in the Anthem breach, according to Symantec. Anthem said the hack likely began in May 2014, but that it didn't realize its systems had been comprised until January. The company, which is one of the largest health insurance providers in the U.S., disclosed the breach in February. Hackers made off with personal data including names, birth dates, member ID numbers and Social Security numbers. Like the Capstone Turbine attack, the Mivast malware was signed with a fake digital certificate.
Symantec reckons spear phishing emails were used to deliver the malware since evidence of a watering hole attack wasn't reported. Anthem's IT staff was probably the attack's intended target, given that the malware was concealed as software related to technology like VPNs, said the security research company.
Anthem didn't immediately respond to a request for comment.