A source code mistake in the GnuTLS library an open-source software building block used in a large number of different Linux distributions to handle secure Internet connections could prove a serious threat to the privacy of Linux users, as developers rush to patch the vulnerability.
Nikos Mavrogiannopolous, the developer of GnuTLS, announced Monday in a mailing list message that he had implemented a fix to the source code that closes the loophole. The flaw would have enabled an attacker to spoof GnuTLS’ system for verifying certificates, exposing supposedly secure connections to stealthy eavesdropping.
By creating a specific type of fake certificate, an attacker could trick GnuTLS into accepting it as genuine, granting access to an otherwise-secure connection. This done, the intruder could monitor traffic flowing through the connection in plain text, and even interject code of his own, potentially opening further avenues of attack.
Mavrogiannopolous, who called the bug “embarrassing,” said that the issue was discovered during an audit performed on behalf of his employer, Red Hat. Some major Linux distributions have already acted to apply Mavrogiannopolous’ fix, according to a security advisory posted by LWN.net. Ubuntu, Debian, Fedora, Red Hat, Oracle, Slackware and SUSE have all rolled out updates aimed at closing the loophole.
The news comes days after Apple patched a similar issue in its own software, which had exposed iOS and OS X users to similar man-in-the-middle attacks. Thanks to the greater consumer reach of Apple’s products, that “goto fail” issue received widespread attention with some commentators even ascribing sinister motivations to Apple’s apparent sluggishness in fixing the flaws.