Slashdot Mirror

← Back to Stories (view on slashdot.org)

Cisco Patches 'Black Hat' IOS Flaw

Posted by Zonk on from the spraypainted-white dept.

thursnick writes "eWeek is reporting that Cisco has finally issued a comprehensive fix for a critical IOS vulnerability that set off a firestorm of controversy at the Black Hat Briefings earlier this year. The patches come more than three months after former ISS researcher Michael Lynn quit his job to present the first-ever example of exploit shellcode in Cisco IOS (Internetwork Operating System), a presentation that landed him in legal hot water. Cisco's advisory effectively confirmed Lynn's summer warning that the flaw could be exploited by remote attackers to execute arbitrary commands or cause a denial-of-service on compromised routers."

20 of 66 comments (clear)

  1. Wow, quick turnaround... by Stormeh · · Score: 3, Funny

    Awesome, and it's only been how many months?

  2. Why not earlier? by ParrotAtSlashdot · · Score: 2, Insightful

    Why on earth did Cisco not release this earlier? It would save people alot of trouble.

    --
    ParrotAtSlashdot
    1. Re:Why not earlier? by scheme · · Score: 5, Informative
      Why on earth did Cisco not release this earlier? It would save people alot of trouble.

      If you read TFA, the bug involved system timers and how they were handled. Given that this probably affects most of the system functions, it's not surprising that it would take a while to make the changes and test it. Think about how long it took to fix the VM bugs in linux 2.4, this probably a change of similar magnitude.

      --
      "When you sit with a nice girl for two hours, it seems like two minutes. When you sit on a hot stove for two minutes, it
  3. Cisco vs. Microsoft by mandreko · · Score: 4, Funny

    looks like Cisco is trying to beat Microsoft for patch times

    1. Re:Cisco vs. Microsoft by Tackhead · · Score: 2, Funny
      > looks like Cisco is trying to beat Microsoft for patch times

      From: <billgatus.of.borg>
      To: <ceo.of.cisco>

      "Johnny, you're doin' a heck of a job!"

  4. patching ciscos... by Anonymous Coward · · Score: 2, Informative

    So now we can all visit CiscoUpdate and have our routers automatically patched....?

    Or do we have to manually evaluate lengthy decision diagrams, check memory requirements, prove that we have legally bought the affected hardware and software, and hope that the monolythic IOS image will not introduce bugs into other areas that are being patched by this fix?

  5. What ever happened... by Anonymous Coward · · Score: 5, Interesting

    So, what ever happened to Michael Lynn? He quit his job and made the presentation but, where is he today? Is he employed? Is he proud of what he did? Does he feel the price he paid was worth what he gave up for 15 minutes in the spot light? Would he recommend his "high road" choice to others in the future? Does he feel that he really made any difference in the end?

    1. Re:What ever happened... by Ckwop · · Score: 4, Informative

      He's alive and well as far as I know. I saw him at Toorcon this year, but didn't speak to him.. (He was a speaker and gave a good talk on Reverse Engineering)

      I know that he has a new job and I while I obviously can't speak for him, I got the impression that he felt as if he did his duty the security community. As an amateur member of that community, I'd thought that he put principle before pay and deserves our respect.

      Simon.

    2. Re:What ever happened... by Anonymous Coward · · Score: 5, Informative

      Mike is working at Juniper, and doing well (Juniper pays better than ISS, apparently, and their code is cleaner than Cisco's, plus they have some ethics). He feels he did the right thing. So do a lot of folks in the US military and intelligence communities, who are very very pissed off at Cisco for exposing them to a security risk of this magnitude and trying to cover it up. They consider Mike a hero, so he has some very useful new friends...

    3. Re:What ever happened... by Wellspring · · Score: 3, Insightful

      I'm glad. I love it when the right thing (for him) is also the Right Thing (ethically).

      The coverup is almost always worse than the crime in these kinds of things. Companies that aren't up-front and honest (trying to protect their reputation) end up trashing their reps. Cisco just created an anecdote for the next time a customer or regulator wants to take a deep, careful look at their security. We can't just take their word for it, and if I were buying routers right now, I'd be much more inclined to look at Juniper than Cisco, even though previously I wouldn't have even considered them.

      It's not magic pixie dust, but making the effort to bring hard-core ethics onstaff is important to me.

  6. The question is....... by 8127972 · · Score: 3, Interesting

    ..... Is this safe enough to deploy or should it be dropped into a test environment of some sort before deploying into a production environment? That assumes of course that admins have the luxury of delaying the deployment of this.

    --
    This is my opinion. To make sure you don't steal it, it's covered by the DMCA.
    1. Re:The question is....... by anticypher · · Score: 5, Informative

      The answer is.....

      This code has been out for a few months now, and many select beta sites have been testing it in production environments. The first few iterations had some serious (crash and reboot every few hours) problems, but it (12.2.15T1thru17) has been in production use on several edge routers for a month with no noticable problems. Cisco didn't just patch the one 'sploit published, they categorised the class of exploits and went about fixing many different possible attack vectors or watching for suspicious behaviour that could indicate a compromised system. That is what took several months even before Michael's talk, and its been in testing (and re-patching and recursion testing) since then. The announcement today is because they are confident their fix is solid, but anyone staying at the bleeding edge of IOS releases has been using it since at least June.

      I'd say its solid, but I'm not rolling out the latest version on everything until others add some real world stress testing. I'm sure there will be several more newly introduced bugs uncovered in the new few months, and the timer checks usually result in a panic reload, not optimal for stable systems with SLAs and big money riding on them.

      I'm also not in a rush to roll this out, because for the moment there are no known exploits running around. Maybe Effugas or some of the IOS engineers (I know you read /.) can add something to this thread.

      the AC

      --
      Hemos is like...sci-fi fans;he thinks technology is cool, but he hasn't bothered to understand the science it's based on
    2. Re:The question is....... by cat6509 · · Score: 2

      yeah you know, i have a *ton* of those spare $50,000.00 TEST routers to throw at the lab.....

      --
      "Tolerance is a virtue of a man without convictions." G.K.Chesterton
  7. Great by Atlantic+Wall · · Score: 3, Funny

    Great, Now how long before everyone implements this and all of the other patches that need to be done on the cisco routers. OK the patch is out, but when will they all be patched, probably another 3-6 mo. So this is a hackers last call sort of, if you have not exploited this yet, time is running out, soon. So get in ur haxoring.

    --
    To Hell with the Queen of England!
  8. Boy oh boy by MightyMartian · · Score: 2, Funny

    Do I feel bad about abandoning Cisco for Linux and IPTables. I mean, there's nothing quite as fun as upgrading Cisco's IOS. It's right up there with root canals in my book of things I like to experience.

    --
    The world's burning. Moped Jesus spotted on I50. Details at 11.
  9. Two scary bits" Completely Compromised by fuzzy12345 · · Score: 2, Interesting
    From TfineA:

    "In many cases, a heap-based overflow in Cisco IOS will simply corrupt system memory and trigger a system reload when detected by the "Check Heaps" process, which constantly monitors for such memory corruption."

    Is anyone else bothered that Cisco figures heap corruption is common enough that a process is running full time on production routers looking for it? I suppose you could view this as proactive, but obviously the process can only look for nonmalicious corruption, and is only statistically likely to find corruption before it causes errors according to how much CPU you give it.

    "In some cases it is possible to overwrite areas of system memory and execute arbitrary code from those locations. In the event of successful remote code execution, device integrity will have been completely compromised,"

    Think about it. Once an exploit is executed against your router, reloading your firmware isn't an option, because that's a function of your firmware, which could be corrupted. Unlike a computer OS virus, which can be circumvented by rebooting and taking control before the corrupted OS does, there's no way to preempt the corruption here. For total peace of mind, you'd either have to replace the (probably not socketed) flash chips, or take the whole unit out back and burn it. Am I wrong? Of course, that's not going to be Cisco's recommended solution.

    --

    Everybody's a libertarian 'till their neighbour's becomes a crack house.
    1. Re:Two scary bits" Completely Compromised by gclef · · Score: 3, Informative

      Cisco doing heap checking is a mark of a reasonable system doing checks on itself. Why is this bad? They almost never use the stack, so they check the memory they are using a lot. It doesn't run often (Lynn found it running about once every 30 seconds or so), and it's a good thing to do. Why complain?

      As for reloading firmware, I don't think you understand Cisco stuff. There is a mini-firmware burned into ROM on all the Routers & Switches...it's called ROMMON mode on the ones that immediately come to mind. If your device firmware is totally thrashed (by a worm, by some damn fool tftp'ing up an image for the wrong router type, etc) you'd just use ROMMON mode to re-load a good image. Now, the real problem is that a worm could trash your flash storage.

      In that case, unless you've got one of the expensive boxes with removable flash cards, you've now got a very expensive paperweight.

  10. Re:Am I affected? by estebanf · · Score: 3, Funny

    Give me your ip... i'll tell you :)

    --
    DON'T STEAL MUSIC!
  11. Re:Am I affected? by Guybrush19 · · Score: 2, Informative

    You aren't vulnerable. The bug was integrated in 12.4(2)T1, so you already have the fix. Older 12.4T versions will be vulnerable, such as 12.4(2)T.

  12. Re:Great news by abaddon314159 · · Score: 2, Informative

    thats funny; it never fails to amaze how many people can't be bothered to read the actual body of an article before commenting on it...

    I'm Michael Lynn, so I know a thing or two about what went on...I DID NOT release any bug details, I DID work with the vendor, the bug in question was patched months before I went on stage as a result of my working with PSIRT, and when I went on stage I didn't disclose any details about any bug...all I did was prove it was possible to exploit bugs on IOS...

    If you don't believe me, then go and find out the exact nature of the vulnerability...you won't be able to do it (at least not without disassembling the thing yourself and rediscovering it) because I never disclosed it to the public...furthermore I disclosed it to the vendor months in advance, waited for them to get a fix out, worked with them all the way until about 48 hours before the talk...they were even going to co-present with me, then someone changed their mind and went into panic mode...

    --Michael Lynn