San Francisco's transport agency has been hit by a malware hack, which temporarily allowed commuters to travel for free on the network.
The malware targeted computer systems across the city's transport network, disabling them with a message that read: "You Hacked, ALL Data Encrypted. Contact For Key(cryptom27@yandex.com)ID:681 ,Enter".
The hackers have issued a ransom demand of 100 Bitcoin, which equates to around $70,000 (56,000), for the return of full access to the system. As a precaution, all ticket machines were turned off during the investigation, according to officials.
Over 2,000 computers belonging to the Municipal Transport Agency (SFMTA), around 25% of the entire network, were infected by the malware, according to San Francisco news site Hoodline. The severity of the attack is still unclear, although the hackers have released documents pointing to essential internal functions including payrolls, email and database servers, and personal computer files of hundreds of employees.
"The incident remains under investigation, so it wouldn't be appropriate to provide any additional details at this point," said agency spokesperson Paul Rose. "At this point, there are not any indications of any impacts to customers."
As the system was unable to process payments, customers were able to ride for free.
The hackers used the HDDCryptor ransomware, also known as 'Mamba', to hijack the Windows OS on the network, encrypting hard drives and locking employees out.
Operating under the pseudonym 'Andy Soalis', often used in HDDCryptor ransom attacks, the hackers gave the agency "one more day" to transfer funds into a provided Bitcoin wallet.
"The SF Muni breach reinforces the repeated concerns many cyber security professionals have over internet-connected systems and the IoT as a whole," said Javvad Malik, security advocate at AlienVault. "Whenever systems are wholly digitised and made accessible publicly, there is a risk that hackers will try to gain access."
"Segregating critical systems from public systems is of utmost importance. This also includes physical segregation, so as not to have access ports or systems in publicly accessible places," added Malik.
The Municipal Transport Agency could still avoid paying the ransom, as the system does have backups that appear to have avoided infection. However, disruption is still likely to affect employees, as one anonymous SFMTA source speaking to KPIX 5 claims: "workers are not sure if they will get paid this week".
ESET security specialist Mark James believes that although the result has been free travel, users should be concerned that transport services have failed to keep data secure.
"If the systems are infected with ransomware, then access to other systems where credit card data may be stored could also be at risk, not to mention the regular data that people often overlook, such as names, addresses, DoB, security questions and answers. All or any of this may be used at a later date to obtain more data or attempted identity theft," added James.
Fare machines are now back up after the outage, however, the agency has so far remained quiet about how they managed to restore access, or if the malware is still in control of parts of the network.
