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Archive Formats Kill Antivirus Products

Posted by kdawson on Tue Mar 18, 2008 01:07 PM
from the fuzz-in-the-zip dept.
Security
nemiloc sends us to the F-Secure blog for breaking news about widespread vulnerabilities in programs that process archive files: "The Secure Programming Group at Oulu University has created a collection of malformed archive files. These archive files break and crash products from at least 40 vendors — including several antivirus vendors... including us." Here is test material from OUSPG and a joint advisory from Finnish and English security organizations. It isn't news that security products can have have security vulnerabilities. What makes this advisory important is that antivirus software is a perfect target. It is run in critical places with high privileges and auto-updates to keep versions coherent.
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Submission: Archive Formats Kill Antivirus Products by nemiloc (1257608)
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  • That's nothing (Score:5, Funny)

    by Anonymous Coward on Tuesday March 18 2008, @01:08PM (#22785666)
    Windows can crash over 9000 products.

  • Secure Platform without Anti-virus (Score:5, Insightful)

    by SpaceLifeForm (228190) on Tuesday March 18 2008, @01:10PM (#22785684)
    Is probably more secure.

    I don't need to mention names, you know.
    • ... if only that secure platform was more customizable and less fruity.

    • Re:Secure Platform without Anti-virus (Score:5, Insightful)

      by JeanBaptiste (537955) on Tuesday March 18 2008, @01:14PM (#22785756)
      Cool. I need to run MS SQL server, it's the only one that my company's workflow software will run on. Also our enterprise app is all written in ASP. We also have lots of Exchange users. It would probably take years and years to convert all these things over to something else, probably with downtime and data loss.

      Your 'solution' may work for some, but probably not for most, and for the rest of us, thats what these articles are posted for!
       

      • Re:Secure Platform without Anti-virus (Score:5, Insightful)

        by TheRaven64 (641858) on Tuesday March 18 2008, @01:21PM (#22785866) Homepage Journal
        That's okay, the money has already been allocated, because you factored in the cost of migrating away from the platform as part of the TCO. You did include migration costs in your TCO calculations when purchasing the workflow software and Exchange, right?
        • No. We factored in the costs of losing our jobs because the PHBs wanted Exchange.

          Seriously. I love Linux, but treating people like they're morons for having to support a Windows system is unrealistic.

          • Re: (Score:3, Informative)

            by Neil Hodges (960909)
            You had to write it up the first time with Exchange (and so forth), didn't you? Wouldn't that have added to the 'TCO' of setting up your first system?

      • Re:Secure Platform without Anti-virus (Score:5, Insightful)

        by Ed Avis (5917) <ed@membled.com> on Tuesday March 18 2008, @01:43PM (#22786174) Homepage

        I need to run MS SQL server, it's the only one that my company's workflow software will run on.
        Have you investigated porting to Sybase? It's pretty similar.

        Also our enterprise app is all written in ASP.
        Have you looked at Chili!Soft ASP? Or if you're using ASP.NET, Mono?

        We also have lots of Exchange users.
        Gotta admit, this is harder to migrate from once all your data is locked up in those binary PST files.

        But you have a point that many people, yourself included, are stuck with Windows. It wouldn't be easy to migrate. Much more convenient to buy some crappy virus scanner and keep the plates spinning.

          • Re:Secure Platform without Anti-virus (Score:5, Informative)

            by Drantin (569921) * on Tuesday March 18 2008, @04:08PM (#22788054)
            Normally, in order to keep the system functioning nicely on large systems, the users will have mailbox limits, in order to keep older mail they create personal archive files (or whatever they're actually called) These archives with the extension of PST allow them to move mail from the exchange server into them and they have room for more mail while keeping the old stuff...
          • I'm sorry, but *any* system that stores email in a binary database is simply lame. Period. Really, the only decent format is something like the Maildir [wikipedia.org] format -- where each message gets its own file. It's as close to elegant for mail storage as you can get these days, easy to backup/restore, less prone to breakage (mbox, here's looking at *you*), and is easy to otherwise massage and manipulate via automated means. Sure, you can't run SQL queries for finding content, but find+grep sure does one hell of a

            • Re: (Score:3, Insightful)

              by Ed Avis (5917)

              I'm sorry, but *any* system that stores email in a binary database is simply lame.
              This is a bit daft; in the end everything is stored in a binary database when it goes to disk. If you trust an database system for storing financial records at your bank, why shouldn't it store your mail? Do you think that Gmail really uses maildirs with one file per message, and good old find+grep for searching?

      • Re: (Score:3, Interesting)

        by fred fleenblat (463628)
        Also, this isn't a FOSS vs. Microsoft thing even though many people make it out to be. For maximum protection against malware I'd actually go for Oracle on Solaris or AIX, all of which are closed source.

      • Re:Secure Platform without Anti-virus (Score:5, Insightful)

        by IllForgetMyNickSoonA (748496) on Tuesday March 18 2008, @02:53PM (#22787118)
        This is a usual argument, I know. However, each time I read it, I can't help but to ask myself "whose fault is it?" The answer is obvious, isn't it?

        It's unfair to pretend non-MS solutions are somehow expensive because it's so hard to break free from MS once you allowed yourself to get hooked into their proprietary world. You could just as well have developed your enterprise apps in something other than ASP, haven't you?

        OK, I know I'm probably barking up the wrong tree here - probably it's not *your* fault after all. But I guess you know what I'm trying to point out.
        • That, and what's the cost to reimplement the system or port the data knowing what you now do?

          Even if Outlook/Exchange were totally a black box, you could still write a screen scraper (like UI testing apps do) and export the data as maildir + data which could be stored in a DB, for anything not email related (calendar, etc).

          You might have a huge clunky 500kloc business system that is essential to the company. But could it be replaced by an off-the-shelf CRM, issue-tracking, and a much smaller leaned reimplem

        • Re: (Score:3, Insightful)

          by jimicus (737525)
          Three (two?) words: Vendor lock-in.

          Unless your employer is prepared to pay for code to be written specifically for every little business requirement that no half-decent Free solution exists for, I defy you to avoid vendor lock-in. Commercial applications with fully documented data schemas are more or less non-existent.

          Email solutions are easy. They've been done to death. So have office applications - wordprocessors, spreadsheets, that kind of stuff.

          Groupware is harder, but not impossible. It becomes muc
    • If only I could get my Apple //c on the Internet.

    • Re: (Score:3, Informative)

      by DaveWick79 (939388)
      Did anyone read TFA and realize that of the programs that were known to be vulnerable, the majority were various brands of Linux?

      • Re: (Score:3, Insightful)

        by orclevegam (940336)

        Did anyone read TFA and realize that of the programs that were known to be vulnerable, the majority were various brands of Linux?
        Actually Linux isn't vulnerable, but some of the common utilities are. Upgrading bzip2 and tar to the latest versions should fix any vulnerabilities. Also hit hard it seems was Symantec with the common library all their utilities use for handling compressed files being compromised, and hence virtually all of their products across the board.
  • So is this evolution, or intelligent design?

  • There's breakage and there's breakage (Score:5, Informative)

    by davidwr (791652) on Tuesday March 18 2008, @01:21PM (#22785876) Homepage Journal
    There's

    1. "I had an exception processing file ABC.ZIP, skipping file,"
    2. Crashing and dying without handling the exception, and
    3. Being exploited due to an unexpected condition.

    The first lets viruses hide in carefully-mis-crafted archives.
    The second lets viruses deactivate antivirus software.
    The third lets viruses 0wn j00.

    Some AV software is smart enough to log instances of #1.

      • Re:There's breakage and there's breakage (Score:5, Interesting)

        by mea37 (1201159) on Tuesday March 18 2008, @02:24PM (#22786722)
        Really smart AV software wouldn't make assumptions about the contents of the file (eliminating #3), would always check for exceptions (eliminating #2), and would treat a processing exception pretty much like a virus (neutralizing #1).

        Very little software in practice is that smart. But with AV, you know you're at war with the file you're scanning. Any AV vendor caught by this should be embarrased.

  • Old Problem (Score:5, Informative)

    by Detritus (11846) on Tuesday March 18 2008, @01:28PM (#22785996) Homepage
    Similar problems have appeared in other file formats and packet formats. Even without deliberate attacks, data corruption can crash applications and systems that are insufficiently paranoid about the data that they receive and process. Do you want it fast or do you want it correct?

    • Re: (Score:3, Insightful)

      by Xtravar (725372)

      Do you want it fast or do you want it correct?
      Do I want it fast 99.99999999% of the time with a 0.00000001% chance of incident, or do I want it slow 100% of the time with a 0% chance of incident?

      If correcting the repercussions of the incident takes less time than the total time lost by doing things the correct way, then I will take the fast way, please.

      • Re: (Score:3, Insightful)

        by DRAGONWEEZEL (125809)
        You just did "Cost benefit analysis" or sometimes called Risk Analysis.

        That is the same thing that says, do I leave an unsecured wireless AP, or a lightly secured WEP AP that shows I did at least due dilligence?

        For personal Machines, I'd take the fast way, for shure, assuming data is backed up regularly.

        For corporate machines,(in general,Caveat emptor, and risk assesment would need to be performed on a per machine basis.) I wouldn't trust an icecubes chance in hell (hey, what if Satan has a freezer?), it'd

  • It is run in critical places with high privileges and auto-updates to keep versions coherent.
    run tar at low privileges, then scan the pipe like a normal file.
    for most files theres no need to give the scanner an privaleges
    only needs read access to itself and system files 90% of the time.

    in fact even on windows, why do virus scanners need high privileges?
    • so they can scan stuff at system level, update them selfs without need a admin to log on to the system, to be able to delete files, make it so that limited uses can trun off the scanners/ and so on.
    • I'm guessing it's because they run as a filesystem filter driver and so need privileges to attach to the filesystem layer. They also need to poke about in memory and attach to running processes (eg attach to Outlook to scan incoming mail). It should be possible to separate the data capture portion from the analysis portion but it would probably be much harder to design and test.
      • isnt that exactly where a unix aproach would pay off.
        a root outlook looker, looks at outlook (but the looker is small so hard to exploit)
        a non-root unzip, unzips and passes it on
        a non-root scanner, to scan the file then pass on the conclusion
        a root cleaner, to take any actions (may not even need root)

        by reducing the code that runs with root privileges you reduce the chances of an exploit in root code.

    • Re: (Score:3, Informative)

      by Ephemeriis (315124)

      in fact even on windows, why do virus scanners need high privileges?

      Typically, on a Windows system, antivirus software will embed itself into the operating system fairly deeply. They usually scan all file I/O in real-time, watch memory for suspicious things, and sandbox much of what is run. It isn't as simple as just scanning files here and there. Most Windows antivirus software installs itself (or parts of itself) as a service and starts running even before the shell comes up.

  • Hrm (Score:5, Informative)

    by Shadow-isoHunt (1014539) on Tuesday March 18 2008, @02:19PM (#22786658) Homepage
    Details on the latest examples
    http://nvd.nist.gov/nvd.cfm?cvename=CVE-2008-0308 [nist.gov]
    http://nvd.nist.gov/nvd.cfm?cvename=CVE-2008-0309 [nist.gov]

  • Bad programming (Score:3, Interesting)

    by dabadab (126782) on Tuesday March 18 2008, @02:26PM (#22786738)
    You DO test your product with malformed archives, don't you? I know I do. And our product - if possible at all - ignores the problems and extracts the archive anyway or if it's borked beyond recovery then report it as such. But crashing?... Please.
  • A zip file can crash the anti-virus software when it tries to scan it? Is that what this is about? But why does it have to be an archived file, and not just any file? I was under the impression that any file could possibly crash any program that trips over an unexpected error....

    Also if you need to unzip a random file for the virus to release, then how is that much different from your typical .exe attachments that you're not suppose to execute.

  • That's been going on for ages!!! (Score:5, Interesting)

    by mrmeval (662166) <mrmeval@gmail. c o m> on Tuesday March 18 2008, @05:26PM (#22788974)
    My favorite is using pkzip to zip up a ~200meg+ file to kill automated virus checkers. ;) The harddrives in the hey day of command line pkzip were small and this would kill some twits BBS because the virus checker would blindly unzip the file then check it without checking that it would fill the drive. The next version of the software just looked at what the zip file said..but you could edit the zip to say anything and it would still decompress the whole file.
    The next version did fix that finally...for pkzip. ;)

    Using social engineering that is rather inept by todays standards I convinced several people on usenet to not read the text telling that it could cause problems but to just blindly open the doubly zipped file (it gets smaller when doubly zipped a certain way so I made it 2G to start).

    I did the same thing with PGP which could allow one to kill an encrypted anonymous remailer and I also nailed several people by posting the PGP message with a passphrase. PGP compresses files prior to encryption. I didn't mess with the remailer without asking permission. The person running it was a bit surprised.

    Linux commands:
    dd if=/dev/zero of=hi bs=1024 count=200512
    zip hi.zip hi
    Result -rw-r--r-- 1 bogus bogus 199411 2008-13-48 18:04 hi.zip

    zip -9 ho.zip hi.zip
    Result -rw-r--r-- 1 bogus bogus 846 2008-30-81 18:13 ho.zip
    I'm not sure why but using -9 to start does not make the original super small it only works the second time.

    If you want to assault a fractal compressor, just insert a non-finite automata and have at them. You get points if it's video and draws frame after frame of something inappropriate.

    • Re: (Score:2, Informative)

      by thyrf (1059934)
      It needs to be identified as such first anyway and that's what's crashing it.

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