"This vulnerability is located within the Dropbear daemon and occurs due to the way the server manages channels concurrency. A specially crafted request can trigger a use after free condition which can be used to execute arbitrary code under root privileges provided the user has been authenticated using a public key (authorized_keys file) and a command restriction is enforced (command option).

Solution: Upgrade to version 2012.55 or higher."


Mercurial entry for the upgraded code: https://secure.ucc.asn.au/hg/dropbear/rev/818108bf7749

So does this means that I have to upgrade every dropbear on all my OpenWRT routers? What OpenWRT versions are affected??

Please help, it looks like an ASAP task!

  • 1
    Could you add some more details of the vulnerability in the text of your question? Otherwise, it's fairly useless if the links ever die. – Iszi Feb 25 '12 at 0:22
  • LEDE is under active development. Last commit to dropbear was few days ago: github.com/lede-project/source/tree/master/package/network/… The last build for x86_64 arch is dropbear_2017.75-2_x86_64.ipk 93.0 KB Sun Jun 18 14:58:13 2017 – user7568519 Jul 14 '17 at 5:18

The latest Open-WRT version is 2 years old now. If you have not upgraded individual services, then you will need to perform this upgrade.

From Dropbear: "Security update 2012.55 — releases from 0.52 to 2011.54 are potentially vulnerable to code execution as root by an authenticated user if a command="..." option is used in authorized_keys. Release 2012.55 fixes the problem."

Also, consider switching to another router OS replacement that is under more active development, like DD-WRT.

  • "by an authenticated user" - so it's not a remote code execution, ok – LanceBaynes Mar 15 '12 at 14:17
  • 5
    Those appear reversed; it's OpenWrt that's in active development, while DD-WRT has stagnated. Though it may have been the other way round a year ago when you wrote this. The current release of OpenWrt, Attitude Adjustment, has dropbear 2012.55. – Michael Hampton Feb 20 '13 at 4:51

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