Goto Apple: GnuTLS falls foul of SSL certificate verification issues

Goto Apple: GnuTLS falls foul of SSL certificate verification issues

Summary: An audit conducted by Red Hat has turned up an SSL certificate verification vulnerability in all versions of GnuTLS.

TOPICS: Security, Apple

Any version of a widely installed security library has been found to be vulnerable to specially crafted certificates that would allow a man-in-the-middle attack against applications using GnuTLS.

Found in an audit conducted by Red Hat, GnuTLS failed to properly handle "certain errors" encountered during SSL certificate verification, and would report successful verification of the SSL certificate when it should have ended in failure. The library would accept "specially crafted" certificates, even if they were not issued from a trusted certificate authority.

"A vulnerability was discovered that affects the certificate verification functions of all GnuTLS versions," a security advisory on the GnuTLS site states. "A specially crafted certificate could bypass certificate validation checks."

As the issue affects all version of the library, the only recourse is to update to versions 3.2.12 or 3.1.22 of the library, or apply a patch for the 2.x GnuTLS branch.

The error in GnuTLS is similar to the goto fail SSL certificate handling issue that Apple patched in its iOS and, eventually, OS X operating systems last week.

In the days between the iOS and OS X updates, security researchers were able to show that it was possible to build a man-in-the-middle attack to capture all SSL traffic from a vulnerable Apple device.

In both cases, incorrect goto calls have been the root cause of the security issues.

Topics: Security, Apple


Chris started his journalistic adventure in 2006 as the Editor of Builder AU after originally joining CBS as a programmer. After a Canadian sojourn, he returned in 2011 as the Editor of TechRepublic Australia, and is now the Australian Editor of ZDNet.

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  • Great job, Nikos Mavrogiannopoulos

    of the Red Hat Security Technologies Team for finding this bug.
  • not even close to being like Apple's goto fail

    This one needs specific conditions for the exception to occur.
    Apple's goto fail is like having door locks that can be unlocked using a screwdriver.
    • While certainly not as bad

      "not even close" is a strong choice of words. It is a fairly similar error, and to someone who knows the error, pretty much as easy to exploit with a MIM attack.

      People should stop making excuses for their favoured platforms. I chided a lot of other Mac users for making excuses for Apple when the TLS bug became known... no favours are done your platform by excusing sloppiness. Users should always be a demanding clientele.
      • not even close

        The GNUTLS flaw requires you to have a valid version 1 certificate from a trusted CA in order to create the error condition. You cannot just start with nothing like Apple goto fail. You need an older valid cert - stolen, inside job , whatever.
        It is not a failure in processing invalid certs like Apple.
        While still unacceptable, it is not even close to the security hole of Apples goto fail.
        Lastly, error handling flaws like this occur quite a lot. You just have to read a page or two of CVE lists to see it is littered with error handling vulnerabilities in almost any OS. While the GNUTLS flaw is probably more severe in potential than most error handling flaws, it is not even on the same continent as the goto fail bug.
  • What is CHS?

    Cylinder-head-sector, also known as CHS, was an early method for giving addresses to each physical block of data on a hard disk drive. In the case of floppy drives, for which the same diskette medium can be low-level formatted to different capacities, this is still true. Although CHS values no longer have a direct physical relationship to the data stored on disks, pseudo CHS values (which can be translated by disk electronics or software) are still being used by many utility programs.
  • My how this stuff spreads

    Just amazed how quickly these flaws get applied to real world attacks. Is 2014 the year for increased attacks and exploits? So far its been Apple, routers, and retail hacking of personal data. What's next?
  • So, how long has

    This exploit been out there?
    • Since 2005.

      But since it open source, thousands of people have known about it for years and if was fixed almost immedia.... Oh wait.
  • Re: GnuTLS falls foul of SSL certificate verification issues....

    Lets just set the record straight regarding the SSL/TLS fix for OS X. It was only logical that the fix was released at the same time as the OS X 10.9.2 update. Furthermore it was iOS devices that were most at risk and most vulnerable . So to fix iOS before OS X made perfect sense.

    With regards to the vulnerability discovered by Red Hat it only goes to cement the fact that this threat exists cross platform and is not something that just plagues Apple.

    Anti-Apple Trolls take note !
    • what?

      OSX is just as affected as iOS since it affects icloud services. Furthermore, OSX flaw could allow further propogation thru private networks the Mac is on. Furthermore, OSX usually handles more data and has less data sandboxing than iOS so if anything OSX needs it more.
  • Many eyes?

    I assume Redhat did this because of the publicity over Apple, but what happened to the "many eyes make fewer bugs" argument? Is nobody routinely auditing the code, over and over? :)

    Color me unsurprised.

    However, good job Redhat for finding the bug!
    • Both errors were in open source projects

      SecureTransport is part of Apple's open source projects (Darwin and WebKit.) WebKit is one of the most scrutinized open source projects on the web - surprising no one caught it.
      • Ardwolf: "good job Redhat for finding the bug!"

        Indeed, but the "many eyes" proponents should take note because the Red Hat employee credited with finding and fixing this vulnerability, Nikos Mavrogiannopoulos, is one of the two "main authors" of gnutls:
        Rabid Howler Monkey