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Encryption Security Linux

Analysis of Linux Backdoor Used In Freenode Hack 37

An anonymous reader writes "A detailed analysis has been done of the Linux backdoor used in the freenode hack. It employed port knocking and encryption to provide security against others using it. This seems a little more sophisticated than your average black-hat hacker.
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Analysis of Linux Backdoor Used In Freenode Hack

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  • by Anonymous Coward on Tuesday October 14, 2014 @06:29PM (#48145487)

    So a common method of securing parts of systems (port knocking) was used by nefarious software to protect itself.

    "This seems a little more sophisticated than your average black-hat hacker."

    From the article...
    "Whilst the handshake and data security mechanisms are arguably well designed the persistence mechanism isn’t in any sense stealthy. This particular rootkit would be easily detectible using tools as Tripwire and Rootkit Hunter. ...
    While the techniques used are well engineered they are certainly not unique. For example netfilter hooks were discussed in the context of rootkits back in a 2003 Phrack article titled ‘Kernel Rootkit Experiences‘. Similarly port knocking and RC4 encryption for concealment and transport security are not highly sophisticated yet are sound approaches if developing a rootkit."

    Doesn't seem so special after all.

    • by grcumb ( 781340 ) on Tuesday October 14, 2014 @06:57PM (#48145709) Homepage Journal

      Doesn't seem so special after all.

      Well, full marks for that clever little bit of sleight of hand that allowed them to set up persistent connectivity without hard-coding addresses. I like the way they use the combination of port and sequence number to determine the remote address, and packet window size to set the remote port. It was also pretty interesting that the software could take its sweet time between 'magic' packets, allowing it to obscure itself in incoming traffic.

      But yeah, it's a clever riff on well-known rootkit tools. And it's nothing that shouldn't have been discovered in a moderately well-run security environment. I mean, we are talking about an altered boot script, new rules running in iptables, and additional new binaries on the system. You would expect that sort of thing to be found before too long.

      But one thing I would very much like to know is how this rootkit got installed in the first place. There's nothing about that in TFA.

      • by rtb61 ( 674572 ) on Tuesday October 14, 2014 @07:04PM (#48145747) Homepage

        They only thing special about this rootkit is that is clearly designed to be installed by an insider. The sort of thing that NSA financially or via extortion corrupted network security types, would install. I'll bet that many foreign countries will not be accepting their version of H1B when they come from the US, in network security jobs.

        • by cavreader ( 1903280 ) on Tuesday October 14, 2014 @10:34PM (#48146833)

          China, Russia, N. Korea, France, England, Germany, Israel, Japan, Brazil, and basically every other country on the planet with indoor plumbing and broadband internet service all contain governmental security services with ability to create an exploit such as this. And that group is probably dwarfed by the criminal enterprises around the world making money hand over fist by creating, selling, and using sophisticated exploits. So that being said where will you find people to fill your network security jobs after ruling out anyone associated with the US?

      • But one thing I would very much like to know is how this rootkit got installed in the first place. There's nothing about that in TFA.

        That was my question too... how did it get there? I mean, kernel modules don't just magically appear and install themselves... :-P

        • Re: (Score:2, Troll)

          by fnj ( 64210 )

          That was my question too... how did it get there? I mean, kernel modules don't just magically appear and install themselves... :-P

          Using any of the endless parade of exploits that constantly emerge for linux, I would imagine. Why does it matter?
          1) You get root just one time
          2) Then you can install any kind of root kit or do any other kind of goddam random or fiendishly convoluted havoc you can think of

          You know the kind of shabby security joke that Windows turned into? The same thing has happened to linux and

          • by fnj ( 64210 )

            P.S. - for anyone who is bewildered, when I said "now this" I was referring to the SSL 3.0 exploit. The story is close to this one and I was reading both of them. But it all comes together into a giant shitstorm, and it is past the point of criticality.

            Either we are going to abandon the whole internet/OS infrastructure hodgepodge that has proved to be unprotectable and replace it with something that is secure by design, or we are going to have to live with everybody getting constantly pwned. I doubt I will

          • by epyT-R ( 613989 )

            SSL is not linux or bsd specific.

          • by grcumb ( 781340 ) on Wednesday October 15, 2014 @03:09AM (#48147639) Homepage Journal

            If you think I've misinterpreted the problem, please tell me exactly where.

            Right here:

            You know the kind of shabby security joke that Windows turned into? The same thing has happened to linux and BSD

            The security problems that afflict Linux, Mac OS X and, to a much lesser extent, *BSD are fundamentally different in the way they manifest.

            We have yet to see the systemic infestation that characterised Windows in the late '90s and early '00s. There was a time mid-decade when the time it took to for an unattended, freshly installed Windows box to get pwned was estimated to be 20 minutes.

            Heartbleed, Shellshock, the Debian SSH debacle (can't forget that one) and numerous other problems are symptomatic of weaknesses in aspects of the FOSS environment that people used to think (unrealistically) were invulnerable. Instead, what we've discovered is that they're quite susceptible to targeted attack. This difference should not be understated. Windows is an infected system - basically, you can't run it without antivirus. Linux, Mac OS X and numerous other OSes are easily attacked individually, but there are not as yet any exploits that subvert the entire ecosystem.

            None of this is to dismiss how serious the potential threat is. I just want to make it clear that, so far, the danger that we see is different from what we are living with in the Windows world. It's different in quantity and quality.

        • I mean, kernel modules don't just magically appear and install themselves

          At least not until the next version of systemd is released.

    • The most common black-hat software is pretty dumb, e.g. brute force ssh attack, install custom ssh client, attack other machines' ssh with brute force. By comparison this is pretty savy. It sounds like someone was targeting freenode specifically.

  • by Anonymous Coward

    All the features listed can be found part of the open source rootkit named jynx 2.0 programmed in C which has been around for years. It employs socket hijacking for a backdoor access on any outbound service, SSL encryption for communications, root shell access, file and socket hiding from root users, as well as loading into every running application via LD_preload. The only detection is looking at which libraries are attached to your processes in which a live CD needs to be used to remove the files.

  • He totally did.

    http://warrior.logicalnetworki... [logicalnetworking.net]

  • by LazLong ( 757 ) on Wednesday October 15, 2014 @04:24AM (#48147823) Homepage

    The OA uses the term "Linux backdoor," but then goes on to describe it as a add-in kernel module. It's not a backdoor, but rather a rogue kernel module someone has written. The module in question, ipt_ip_udp, isn't part of the Linux kernel. It's merely a module some black hat wrote to provide remote access to an already compromised system. This is just FUD and self-promotion by NCC Group to make what they found sound much more important than it really was, no doubt to increase their client base. What crap.

    To sum up, it isn't a Linux back door and it isn't a vulnerability in the Linux kernel source code. It's merely a rootkit.

    • @LazLong: "To sum up, it isn't a Linux back door and it isn't a vulnerability in the Linux kernel source code. It's merely a rootkit."

      Thank you, a bit more accurate and informative than the main article ..
  • How does this 'Linux backdoor' get onto the system in the first place?

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