Gray-market exploit brokers are alive and kicking, with the latest sign of this flourishing market coming in the form of a bidding war for Signal messaging app zero-days from a relatively new entrant. 

Russia-based OpZero went on the record recently with a $1.5 million offer for Signal remote code execution (RCE) exploits, more than tripling the relatively stable high-water mark for that app offered by American firm Zerodium.

Cybersecurity experts say that this particular bidding war indicates the Russian government's desperation to gain surveillance capabilities over Ukrainians utilizing Signal to communicate. But the price movement on this front also offers a microcosmic look into the broader reliance of gray-market customers (most typically governments) on intermediary brokers.

The Shadowy "Gray Hat" World of Cybersecurity Exploit BrokersThese brokers are sometimes independent dealers, other times thinly cloaked fronts for nation-state intelligence agencies, who buy from security researchers interested in cashing in on their exploit work. The market works on an "ask me no questions, and I'll tell you no lies" basis, researchers say. Brokers have no scruples in working with both white- and black-hat security experts — and exploit developers don't ask how or by whom their exploits will be used. The arrangements put this market in a swampy middle ground between the vendor-oriented, highly structured vulnerability bug-bounty market and the chaotic and overtly criminal dealings of the Dark Web, dominated by black hats."Exploit brokers function as market makers by contracting with suppliers (security researchers) managing an inventory of exploits, and selling to buyers (actors who deploy offensive cyber-operations)," according to a recent paper on the gray-market exploit world presented at the 21st Workshop on the Economics of Information Security (WEIS’22) in Tulsa, Okla., earlier this year. "In doing so, brokers can more efficiently manage transaction costs relative to suppliers and buyers directly contracting with each other. Additionally brokers provide a layer of insulation against reputation and legal fallout," the paper explained, adding that the price of exploits has grown by 1,240% over the last six years in the gray market.

War in Ukraine Sparks Signal Exploit Bidding War

Perhaps one of the most public and prolific players in the market is Zerodium, an American firm with an obscured customer list of "government institutions mainly from Europe and North America," according to the company's FAQ. 

The firm offers as much as $2 million for iOS flaws and presents many public offers for exploits in a range of operating systems and applications. The company has had a standing offer since 2017 of "up to" $500,000 for exploits of Signal and other social messaging apps, including Facebook Messenger, WhatsApp, and Telegram.

The entrance of OpZero into this mix with an offer of three times that amount, which has experts such as security researcher The Grugq postulating that the company is a stand-in for Russian intelligence services that are "desperate" for Android and Signal exploits.

"Android has an almost 80% market share in Ukraine, and Signal has over 2 million daily active users," The Grugq recently wrote. "Android phones with Signal are robust security platforms. They’re not military equipment, but they’re perfectly capable of providing protection against a wide range of security threats. Including nation state level threat actors. Russia appears to be lacking an Android or Signal capability."