Lockheed Martin has reportedly suspended remote access to email and corporate apps following the discover of a network intrusion that may be linked to the high-profile breach against RSA earlier this year.

The manufacturer of F-22 and F-35 fighter planes has reset passwords in response to a "major internal computer network problem", according to two anonymous sources and an unnamed defence official, Reuters reports. Technology blogger Robert Cringely reports that Lockheed detected the suspected breach on Sunday. He adds that an estimated 100,000 personnel will be issued with new tokens before remote access is restored, a process likely to take at least a week.

The incident involves the use of SecurID token from RSA to log into accounts and may be tied to, or at least use information extracted from, an attack on RSA Security's systems back in March. Unknown (or at least unidentified) hackers broke into the EMC divisions network and made off with unspecified information related to SecurID, possibly the seed used to generate one-time codes supplied by the token.

RSA has publicly explained how the attack might have taken place but not what was obtained. It did however warn that the breach may affect the level of protection offered by SecurID tokens, which are very widely used for two-factor authentication.

Potential hackers would still need a lot of information – including user account names and PINs – to break into corporate email or remote access systems protected by RSA SecurID. Our best guess is that Lockheed detected an attempt to access just this information and responded by suspending remote access and shutting down portions of its network as a precaution.

The data held by Lockheed would be of profound interest to agents of a hostile power. The level of sophistication of the original RSA hack strongly points towards state-sponsored hackers, hence Lockheed's response is a proportionate response to an all too real cyberespionage threat. ®