It’s not usually {that a} zero-day vulnerability causes a community safety vendor to induce prospects to bodily take away and decommission a whole line of affected {hardware} — versus simply making use of software program updates. However consultants say that’s precisely what transpired this week with Barracuda Networks, as the corporate struggled to fight a sprawling malware risk which seems to have undermined its electronic mail safety home equipment in such a basic method that they will not be safely up to date with software program fixes.

The Barracuda Electronic mail Safety Gateway (ESG) 900 equipment.

Campbell, Calif. based mostly Barracuda stated it employed incident response agency Mandiant on Might 18 after receiving experiences about uncommon site visitors originating from its Electronic mail Safety Gateway (ESG) gadgets, that are designed to sit down on the fringe of a corporation’s community and scan all incoming and outgoing electronic mail for malware.

On Might 19, Barracuda recognized that the malicious site visitors was making the most of a beforehand unknown vulnerability in its ESG home equipment, and on Might 20 the corporate pushed a patch for the flaw to all affected home equipment (CVE-2023-2868).

In its safety advisory, Barracuda stated the vulnerability existed within the Barracuda software program part accountable for screening attachments for malware. Extra alarmingly, the corporate stated it seems attackers first began exploiting the flaw in October 2022.

However on June 6, Barracuda immediately started urging its ESG prospects to wholesale rip out and change — not patch — affected home equipment.

“Impacted ESG home equipment have to be instantly changed no matter patch model stage,” the corporate’s advisory warned. “Barracuda’s advice presently is full substitute of the impacted ESG.”

In a press release, Barracuda stated it is going to be offering the substitute product to impacted prospects for free of charge, and that not all ESG home equipment have been compromised.

“No different Barracuda product, together with our SaaS electronic mail options, have been impacted by this vulnerability,” the corporate stated. “If an ESG equipment is displaying a notification within the Person Interface, the ESG equipment had indicators of compromise. If no notification is displayed, we have now no cause to consider that the equipment has been compromised presently.”

However, the assertion says that “out of an abundance of warning and in furtherance of our containment technique, we suggest impacted prospects change their compromised equipment.”

“As of June 8, 2023, roughly 5% of energetic ESG home equipment worldwide have proven any proof of identified indicators of compromise because of the vulnerability,” the assertion continues. “Regardless of deployment of extra patches based mostly on identified IOCs, we proceed to see proof of ongoing malware exercise on a subset of the compromised home equipment. Due to this fact, we want prospects to exchange any compromised equipment with a brand new unaffected machine.”

Rapid7‘s Caitlin Condon referred to as this outstanding flip of occasions “pretty beautiful,” and stated there seem like roughly 11,000 susceptible ESG gadgets nonetheless linked to the Web worldwide.

“The pivot from patch to complete substitute of affected gadgets is pretty beautiful and implies the malware the risk actors deployed someway achieves persistence at a low sufficient stage that even wiping the machine wouldn’t eradicate attacker entry,” Condon wrote.

Barracuda stated the malware was recognized on a subset of home equipment that allowed the attackers persistent backdoor entry to the gadgets, and that proof of information exfiltration was recognized on some techniques.

Rapid7 stated it has seen no proof that attackers are utilizing the flaw to maneuver laterally inside sufferer networks. However which may be small comfort for Barracuda prospects now coming to phrases with the notion that international cyberspies most likely have been hoovering up all their electronic mail for months.

Nicholas Weaver, a researcher at College of California, Berkeley’s Worldwide Pc Science Institute (ICSI), stated it’s probably that the malware was capable of corrupt the underlying firmware that powers the ESG gadgets in some irreparable method.

“One of many objectives of malware is to be arduous to take away, and this implies the malware compromised the firmware itself to make it actually arduous to take away and actually stealthy,” Weaver stated. “That’s not a ransomware actor, that’s a state actor. Why? As a result of a ransomware actor doesn’t care about that stage of entry. They don’t want it. In the event that they’re going for information extortion, it’s extra like a smash-and-grab. In the event that they’re going for information ransoming, they’re encrypting the information itself — not the machines.”

Along with changing gadgets, Barracuda says ESG prospects must also rotate any credentials linked to the equipment(s), and test for indicators of compromise courting again to not less than October 2022 utilizing the community and endpoint indicators the corporate has launched publicly.

Replace, June 9, 11:55 a.m. ET: Barracuda has issued an up to date assertion concerning the incident, parts of which at the moment are excerpted above.