That finding was first reported by security journalist Brian Krebs, who discovered the information in a post made on an underground, Russian-language cybercrime forum by an associate of "Paunch," the creator of Blackhole.
"We are setting aside a $100K budget to purchase browser and browser plug-in vulnerabilities, which are going to be used exclusively by us, without being released to public (not counting the situations, when a vulnerability is made public not because of us)," according to a translation of the post published by Krebs. "Not only do we purchase weaponized (ready) exploits, but also their descriptions and proof of concepts (with subsequent joint work with our specialists)."
The Blackhole toolkit is used to infect legitimate websites with malicious code, after which the infected website can be used to launch drive-by attacks that target browser vulnerabilities and then compromise the underlying PC. From there, attackers can steal login credentials for financial websites, make the PCs serve as spam relays or press the PCs into service as part of a botnet.
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Blackhole isn't available to buy. Rather, it can only be rented for about $50 per day, $700 for three months or $1,500 for one year.
Success in the crimeware toolkit market is predicated on selling -- or in the case of Blackhole, renting -- software that successfully infects as many PCs as possible in the shortest possible amount of time. Accordingly, the most successful crimeware creators tend to rapidly add exploits for the latest known vulnerabilities to their software to help their buyers or subscribers compromise more PCs, thus maximizing their potential illicit revenue.
Not surprisingly, the gang behind the Blackhole toolkit regularly updates the software to allow it to exploit the latest zero-day flaws. Last year, for example, an exploit for a Java zero-day vulnerability was added to Blackhole less than 12 hours after the bug was first detailed publicly. The severity of the flaw and as its inclusion in a crimeware toolkit -- as well as in the open source Metasploit framework -- led security experts to recommend that Java be deactivated on all PCs, pending a fix from Oracle.
Blackhole's creator, Paunch, last year told Krebs via IM that the one exploit could have been worth $100,000 if sold on the zero-day vulnerability market. As that suggests, Paunch already seemed to have a familiarity with the buying and selling of zero-day vulnerability information.
Evidence that Blackhole has been paying off handsomely for its creators comes not just from Paunch's apparent $100,000 zero-day vulnerability budget, but also from the fact that the Blackhole gang now rents not just the basic version of the crimeware toolkit, but also a $10,000 per month exploit pack called the Cool Exploit Kit, which first began appearing in October 2012. So far, the pricey exploit pack has only been used by two ransomware criminal gangs, according to researchers. In particular, one of the gangs has been launching Raveton malware attacks that lock people's PCs, then demand the user pay a fine, supposedly to the FBI or another government agency. In reality, the money goes into the criminals' coffers.
In the case of Cool, the exploit pack last year included an innovative Windows vulnerability that first appeared in Duqu, according to a French information security researcher known as "Kafeine." Duqu was reportedly the product of a U.S. cyber-weapons program, thus illustrating that yesterday's espionage tool quickly becomes the inspiration for today's cybercrime malware.
Indeed, speaking recently by phone, Bit9 CTO Harry Sverdlove warned that one side effect of government-commissioned espionage malware is that it helps criminals rapidly advance the state of the art of their own malicious code. "It raises the bar for everyone -- the techniques, if not the source code," he said.