Threat Level: green Handler on Duty: Remco Verhoef

SANS ISC: OpenSSL Security Advisory including Lucky Thirteen: Breaking the TLS and DTLS Record Protocols - SANS Internet Storm Center SANS ISC InfoSec Forums


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OpenSSL Security Advisory including Lucky Thirteen: Breaking the TLS and DTLS Record Protocols

OpenSSL has issued an advisory regarding updates released to address the following issues:

  • SSL, TLS and DTLS Plaintext Recovery Attack (CVE-2013-0169)
    • Affected users should upgrade to OpenSSL 1.0.1d, 1.0.0k or 0.9.8y
  • TLS 1.1 and 1.2 AES-NI crash (CVE-2012-2686)
    • Affected users should upgrade to OpenSSL 1.0.1d
  • OCSP invalid key DoS issue (CVE-2013-0166)
    • Affected users should upgrade to OpenSSL 1.0.1d, 1.0.0k or 0.9.8y.    

    
The SSL, TLS and DTLS Plaintext Recovery Attack (CVE-2013-0169) is particularly interesting as described in Lucky Thirteen: Breaking the TLS and DTLS Record Protocols.

From their writeup (AlFardan and Paterson):
It's called Lucky 13 because the TLS MAC calculation includes 13 bytes of header information (5 bytes of TLS header plus 8 bytes of TLS sequence number) which, in part, makes the attacks possible. In the context of the attacks, 13 is lucky from the attacker's perspective. At a high level, these attacks can be seen as an advanced form of the padding oracle attack. These new attacks against TLS and DTLS allow a Man-in-the-Middle attacker to recover plaintext from a TLS/DTLS connection when CBC-mode encryption is used. The attacks arise from a flaw in the TLS specification rather than as a bug in specific implementations.
Read Nadhem J. AlFardan and Kenneth G. Paterson's full paper here.

The attacks apply to all TLS and DTLS implementations that are compliant with TLS 1.1 or 1.2, or with DTLS 1.0 or 1.2 as well as implementations of SSL 3.0 and TLS 1.0 that incorporate countermeasures to previous padding oracle attacks. Variant attacks may also apply to non-compliant implementations.

Fresh bits available via the OpenSSL project page.

Russ McRee | @holisticinfosec

 

 

 

Russ McRee

178 Posts
ISC Handler
Is there any reports of proof-of-concept or actual exploitation of this weakness beyond the writeup?
IMFerret

10 Posts
Not as of yet, stay tuned.
Russ McRee

178 Posts
ISC Handler

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