Security professionals this week gave a cautious thumbs-up to the San Francisco Municipal Transit Agency (SFMTA) for apparently refusing to pay a $73,000 ransom to attackers who encrypted data on several of its critical systems.

But they faulted the agency for not having enough precautions to protect against the ransomware attack in the first place, particularly because the malware used in the attack was previously known.

The SFMTA on Friday became the victim of a ransomware attack that disrupted some of its internal systems including email. The attack caused several of the "Muni" light rail's ticketing kiosks to become unavailable, forcing the agency to offer free rides for much of the weekend.

Payment kiosks across the agency’s subway stations displayed an "Out of Order" sign while computers in agent booths across the SFMTA system carried a message saying the systems had been hacked and all data encrypted, the San Francisco Examiner said.

At least until late Sunday, Muni drivers were getting routes assigned to them via handwritten notes posted on bulletin boards instead of the usual computer printouts, the Examiner noted.

The SFMTA did not respond to a Dark Reading request seeking information on the number of systems that were impacted in the attack, what might have caused it and whether it has been fully mitigated. And so far, it has disclosed almost nothing publicly on the nature or scope of the attack, the ransom amount that was demanded and whether it made any attempt to get in touch with the attackers or pay the ransom amount.

In a terse statement on the agency blog Monday, SFMTA said the attack had been contained and that it was currently in the process of restoring all affected systems to full operational status. The agency noted that the attack had no impact on transit services or to the safe operation of the Muni Metro system and buses. The statement cited an ongoing investigation of the incident as the reason for not releasing more details.

The Examiner and its media partner Hoodline news, which both contacted the alleged attacker via email, said the Muni’s systems had been infected with HDDCryptor, a ransomware tool discovered earlier this year and for which detections are currently available.

Hoodline said that documents released by the attackers suggest that in addition to email servers, other SFMTA systems including payroll, SQL database servers, and staff training systems were impacted. In all, a total of 2,112 systems, representing about one quarter of all of the agency’s systems were impacted in the attack, according to Hoodline reports. An attacker using the pseudonym Andy Saolis wanted 100 Bitcoins or about $73,000 from the SFMTA in exchange for the decryption keys.

The fact that the agency appears not to have given in to the demand is noteworthy, particularly because it likely lost more in daily revenues by offering the free rides over the weekend, security professionals said.

“Personally, I think it showed strength to not give in to cyber criminals,” says Tyler Moffitt, senior threat research analyst at Webroot. “All of their riders saw the message “You Hacked. ALL Data Encrypted,” so they knew if a decision to pay the ransom was made then it would invoke plenty of judgment,” he says.

But the fact that the agency fell victim to HDDCryptor is troubling, Moffitt says. “It does show a severe lack of preparedness since variants of this threat have been showcased in white papers by many vendors since September.”

From the available information, it would appear that the SFMTA’s readiness for a ransomware attack was average, notes, Matthew Gardiner, cybersecurity strategist at Mimecast. 

Most organizations hit by an attack such as the one the Muni appears to have experienced would be impacted for multiple days. They would typically struggle to recover and probably seriously consider paying the ransom to make the problem go away, Gardiner says. “While this is not good enough in terms of preparedness, I wouldn’t call out the transit authority as being unusually bad based on what’s been reported.”

Justin Fier, director of cyber intelligence and analysis, at Darktrace nots that ransomware victims typically have to consider many factors, including lost revenue, cost to rebuild and cost to get back online when deciding whether to pay a ransom or not.

“Many of the customers I work with have not paid the ransom simply because the attack was caught early, before it escalated into an emergency. In these cases, restoring was not nearly as expensive as paying the ransom,” he says.

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