CVE-2013-4206
MEDIUM severity · CVSS 6.8 · Memory corruption
6.8CVSS MEDIUM
Summary
Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) and possibly trigger memory corruption or code execution via a crafted DSA signature, which is not properly handled when performing certain bit-shifting operations during modular multiplication.
Impact & exploitability
Attack vectorNetwork
Attack complexity—
Privileges required—
User interaction—
Confidentiality impact—
Integrity impact—
Availability impact—
Exploit probability (EPSS)2%
AV:N/AC:M/Au:N/C:P/I:P/A:P
Affected products we track (1)
Recommendation
Apply the vendor fix in your normal patch cycle. Open any affected product above for its exact safe version.
Official patch: http://svn.tartarus.org/sgt/putty/sshbn.c?sortby=date&r1=9977&r2=9976&pathrev=9977 ↗
Additional information
- NVD record
- http://svn.tartarus.org/sgt/putty/sshbn.c?sortby=date&r1=9977&r2=9976&pathrev=9977Patch
- http://secunia.com/advisories/54379Advisory
- http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/vuln-modmul.htmlAdvisory
- http://lists.opensuse.org/opensuse-updates/2013-08/msg00035.html
- http://secunia.com/advisories/54533
- http://www.debian.org/security/2013/dsa-2736
- http://www.openwall.com/lists/oss-security/2013/08/06/11