[SECURITY] [DSA 2736-1] putty security update
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512
- -------------------------------------------------------------------------
Debian Security Advisory DSA-2736-1 security@debian.org
http://www.debian.org/security/ Salvatore Bonaccorso
August 11, 2013 http://www.debian.org/security/faq
- -------------------------------------------------------------------------
Package : putty
Vulnerability : several
Problem type : local (remote)
Debian-specific: no
CVE ID : CVE-2013-4206 CVE-2013-4207 CVE-2013-4208 CVE-2013-4852
Debian Bug : 718779
Several vulnerabilities where discovered in PuTTY, a Telnet/SSH client
for X. The Common Vulnerabilities and Exposures project identifies the
following problems:
CVE-2013-4206
Mark Wooding discovered a heap-corrupting buffer underrun bug in the
modmul function which performs modular multiplication. As the modmul
function is called during validation of any DSA signature received
by PuTTY, including during the initial key exchange phase, a
malicious server could exploit this vulnerability before the client
has received and verified a host key signature. An attack to this
vulnerability can thus be performed by a man-in-the-middle between
the SSH client and server, and the normal host key protections
against man-in-the-middle attacks are bypassed.
CVE-2013-4207
It was discovered that non-coprime values in DSA signatures can
cause a buffer overflow in the calculation code of modular inverses
when verifying a DSA signature. Such a signature is invalid. This
bug however applies to any DSA signature received by PuTTY,
including during the initial key exchange phase and thus it can be
exploited by a malicious server before the client has received and
verified a host key signature.
CVE-2013-4208
It was discovered that private keys were left in memory after being
used by PuTTY tools.
CVE-2013-4852
Gergely Eberhardt from SEARCH-LAB Ltd. discovered that PuTTY is
vulnerable to an integer overflow leading to heap overflow during
the SSH handshake before authentication due to improper bounds
checking of the length parameter received from the SSH server. A
remote attacker could use this vulnerability to mount a local denial
of service attack by crashing the putty client.
Additionally this update backports some general proactive potentially
security-relevant tightening from upstream.
For the oldstable distribution (squeeze), these problems have been fixed in
version 0.60+2010-02-20-1+squeeze2. This update also provides a fix for
CVE-2011-4607, which was fixed for stable already.
For the stable distribution (wheezy), these problems have been fixed in
version 0.62-9+deb7u1.
For the unstable distribution (sid), these problems have been fixed in
version 0.63-1.
We recommend that you upgrade your putty packages.
Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: http://www.debian.org/security/
Mailing list: debian-security-announce@lists.debian.org
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.14 (GNU/Linux)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=nzel
-----END PGP SIGNATURE-----
Reply to: