Description
Dropbear SSH Server before 2013.59 generates error messages for a failed logon attempt with different time delays depending on whether the user account exists, which allows remote attackers to discover valid usernames.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | dropbear | 2012.55-1.4 | — |
| Debian 13 | dropbear | 2012.55-1.4 | — |
| Debian 12 | dropbear | 2012.55-1.4 | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 1 repository
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styx00/Dropbear_CVE-2013-4434 ★ 3 · Mar 20, 2016
Dropbear user enumeration (CVE-2013-4434) PoC
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
References
- 55173 third-party-advisory
- https://matt.ucc.asn.au/dropbear/CHANGES
- 62993 vdb-entry
- [oss-security] 20131015 Re: CVE Request: dropbear sshd daemon 2013.59 release mailing-list
- openSUSE-SU-2013:1696 vendor-advisory
- https://support.citrix.com/article/CTX216642
- openSUSE-SU-2013:1616 vendor-advisory
- https://secure.ucc.asn.au/hg/dropbear/rev/d7784616409a