Lucian Constantin
CSO Senior Writer

FortiGuard SSH backdoor found in more Fortinet security appliances

News
Jan 22, 20162 mins

FortiSwitch, FortiAnalyzer and FortiCache were also affected

Network security vendor Fortinet has identified an authentication issue that could give remote attackers administrative control over some of its products.

The issue, which was described as a FortiGuard SSH (Secure Shell) backdoor, was originally disclosed earlier this month by an anonymous researcher, who also published exploit code for it.

Last week, Fortinet said that the problem was not an intentional backdoor, but the result of a management feature which relied on an undocumented account with a hard-coded password. Additionally the company noted that the issue was fixed in FortiOS back in July 2014, after being identified as a security risk by the company’s own product security team.

FortiOS is the operating system that runs on Fortinet’s FortiGuard network firewall appliances. The versions patched in 2014 were FortiOS 4.3.17 and FortiOS 5.0.8, while the newer 5.2 and 5.4 branches have never been affected.

However, after its statement last week, the company began investigating if the same issue also exists in other products and found that some versions of FortiSwitch, FortiAnalyzer and FortiCache are also affected.

“These versions have the same management authentication issue that was disclosed in legacy versions of FortiOS,” the company said in a new blog post.

Customers are strongly advised to upgrade to the newly released FortiAnalyzer version 5.0.12 or 5.2.5, depending on which branch of the software they’re using. The 4.3 branch is not affected.

FortiSwitch users should upgrade to version 3.3.3 and FortiCache users to version 3.0.8 or to the 3.1 branch, which is not affected.

The company has also provided manual workarounds for affected devices that cannot be immediately upgraded. These consist mainly of disabling SSH access to the devices and using the Web-based management interfaces instead.

“As previously stated, this vulnerability is an unintentional consequence of a feature that was designed with the intent of providing seamless access from an authorized FortiManager to registered FortiGate devices,” the company said. “It is important to note, this is not a case of a malicious backdoor implemented to grant unauthorized user access.”

The company is likely trying to differentiate this problem from an SSH backdoor found recently in network firewalls from Juniper Networks, one of its competitors. In Juniper’s case, the backdoor was added to the company’s source code without its knowledge and remained undetected for two years. That incident is reportedly being investigated by the FBI.

Lucian Constantin

Lucian Constantin writes about information security, privacy, and data protection for CSO. Before joining CSO in 2019, Lucian was a freelance writer for VICE Motherboard, Security Boulevard, Forbes, and The New Stack. Earlier in his career, he was an information security correspondent for the IDG News Service and Information security news editor for Softpedia.

Before he became a journalist, Lucian worked as a system and network administrator. He enjoys attending security conferences and delving into interesting research papers. He lives and works in Romania.

You can reach him at lucian_constantin@foundryco.com or @lconstantin on X. For encrypted email, his PGP key's fingerprint is: 7A66 4901 5CDA 844E 8C6D 04D5 2BB4 6332 FC52 6D42

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