-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 - ------------------------------------------------------------------------- Debian Security Advisory DSA-2736-1 security@xxxxxxxxxx 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@xxxxxxxxxxxxxxxx -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) iQIcBAEBCgAGBQJSB+lQAAoJEHidbwV/2GP+6HUQAIGHk0ctuvUFNpPgZtZwGA9W iX2oysndnZLXZmc1zkXhwvPo5fg/+PjdOvYn0cHfrgVb2wXMPAwIAjUwTZ+p2SbF PwaXbjUr3sUJxQLdFoGNytfFeiUtQNj0/r/ylmQB77bgFKSI9iFnveYeNKc51Shb ApaFKIueuYgrPUTt8KquloNvNryuLa0AjhveWsIDdFQVGW6ipAe70T2BohX5QIwh ehzom1sFbEgJpqdPUt6sR7vyBj+mhg9atp3wCQkEJFq5uhrDEL6OrCwpZJ1oClMP a0LSPwESz4iWUzL3eTgB7ENIcAelBQ4LWnVhuTxpaRGoHizmkId6ueMBD9ezJrmH +/vDsBMQLxZuWP1SG7rEoEjJTsJEVQ/D7vu+s6cDuiliOr8IJ/2oXy0WQCDxinCI l7iJaCQcxcGWY5LmW9tO94GW6ptSUW4aROKLt12u1X4VkKjLpyzkGWNNvK4H6vHg 6orNaN8evpEVjj9ZF7Gq93e79ldhSjuj7ZZPcWmZNHdefxT+wxuXUB7flTXSRhlk RaTC5SrqRlmGSUkm0HaRc61iTh/VZbj1Zw+M+mNw1VwTTUbFOH7gWThkbjWr/yC1 HJpGe4Cpdm+289ci50Z/IVC7rKe0QsGW4tvpeS3N3lsvEVLj/skg/UIAnr86zU65 1VnEAudwqB82viZ0ci+C =nzel -----END PGP SIGNATURE-----
