What appears to be a decrypted private key has been extracted from a Cyberoam UTM certificate and published online in a move that could place businesses and users at risk of traffic interception.
The disclosure comes after the security company denied the breach was possible.
The key was posted on the TorProject blog by users who said they extracted it from the generic digital certificate that was previously available for download on the Cyberoam website.
SC contacted Cyberoam for comment but the company had not responded by the time of publication.
While the authenticity of the key could not yet be verified, Sandvik notes it could be imported into any deep packet inspection device and used to intercept traffic from users operating the Cyberoam certificates.
"It is therefore possible to intercept traffic from any victim of a Cyberoam device with any other Cyberoam device - or to extract the key from the device and import it into other DPI devices, and use those for interception," Sandvik wrote on the blog.
Users and businesses could be protected by applying a hotfix issued yesterday by Cyberoam that replaced the generic certificates with unique ones.
The UTM devices would typically be used in small businesses or branch offices of enterprises.
TorProject security researcher Runa Sandvik told SC a pre-sales staffer claimed that the key was potentially extracted from firmware via an old vulnerability.
She rejected that argument.
Witham Laboratories cryptography boffin Peter Filimore noted UTM devices typically did a poor job at key management.
"The majority of these devices I've seen are a PC that has some expansion hardware added and have not been designed with proper key management in mind," Fillmore told SC.
"The lack of Common Criteria or FIPS 140-2 testing of a device like this would indicate to me that it would quickly fail any physical attack."
He said it was best practice to ensure default keys and passwords were pre-expired and new keys were loaded during setup.
"Compounding this is that any private/symmetric key should be unique per device so extracting a key only affects one device, not all devices."
The key disclosure followed an email from the same staffer to Sandvik and uploaded to pastebin that stated: “After continuous brainstorming, [Cyberoam] concluded that there exists a theoretical possibility -- however remote -- of extracting the private key. Given the physical access to the appliance and unlimited time, any static encryption algorithm can be cracked.”
The alleged key was extracted and decrypted within two days of the initial vulnerability disclosure on 3 July, made by Sandvik and OpenSSL's Ben Laurie.
Cyberoam has remained steadfast in its denial that the key could be extracted and downplayed the risk brought by using generic certificates across the units.
It dubbed the latter risk “nullified” before issuing the certificate hotfix.
The UTM devices did not inspect encrypted traffic by default and could be disabled when users visited sensitive websites like online banking, Cyberoam said.
The company told Sandvik in its email: “We appreciate the work you are doing and your contribution to enhance security awareness. We are impressed by your dedication and passion towards network security and share a similar passion to our work.”