oss-sec mailing list archives
Re: CVE request: rpc-gssd is vulnerable to DNS spoofing
From: Kurt Seifried <kseifried () redhat com>
Date: Thu, 04 Apr 2013 11:01:13 -0600
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 04/03/2013 04:43 PM, Vincent Danen wrote:
This has been discussed on the linux-nfs mailing list, so fully public. Just cutting and pasting from our bugzilla: It was reported [1],[2] that rpc.gssd in nfs-utils is vulnerable to DNS spoofing due to it depending on PTR resolution for GSSAPI authentication. Because of this, if a user where able to poison DNS to a victim's computer, they would be able to trick rpc.gssd into talking to another server (perhaps with less security) than the intended server (with stricter security). If the victim has write access to the second (less secure) server, and the attacker has read access (when they normally might not on the secure server), the victim could write files to that server, which the attacker could obtain (when normally they would not be able to). To the victim this is transparent because the victim's computer asks the KDC for a ticket to the second server due to reverse DNS resolution; in this case Krb5 authentication does not fail because the victim is talking to the "correct" server. A patch that prevents this issue has been posted [3]. To workaround this issue, set the IP/host pair in /etc/hosts so that it cannot be spoofed. A good explanation is also available here [4]. [1] http://marc.info/?l=linux-nfs&m=136491998607561&w=2 [2] http://marc.info/?l=linux-nfs&m=136500502805121&w=2 [3] http://marc.info/?l=linux-nfs&m=136493115612397&w=2 [4] http://ssimo.org/blog/id_015.html https://bugzilla.redhat.com/show_bug.cgi?id=948072 Since this is fairly new, I don't think a CVE would have been requested already. Could one be assigned to this?
Please use CVE-2013-1923 for this issue. - -- Kurt Seifried Red Hat Security Response Team (SRT) PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (GNU/Linux) iQIcBAEBAgAGBQJRXbHZAAoJEBYNRVNeJnmTFYEP/1KxHQ6plRr16LsGL2iFEz8L Ku/gGd20IE1tWfoRiLObEsrK3ab8GcTztgQEK3i2YCmQxjF+rPDA4M7a2BH7XSDK tJqH6Ia4PKEXEl+kJsNQaDAkZjvWjOkkzpSNvVc/IQy6NkjcFMXtDh+ySRoRgDhS lo2KMxw0q6KMPNc9fumfKbejhGR5QRm4RwycfmhyE0t7JcoomjgR78bTwRIR1gL4 8PxA0E3P/7b5gfEq0eid8AN9GpiiDab7LmWVnTMPsirsKEiq6CEu6p7WICT7CsCH Xfz3ao24XO6LDmIJOnR7ecjafQcrdYFJDJM67Nh+TCxjjLrYVYrPIKptjJl7DPsq ou/FXfeHNR3BNiSg36NZZ0UnMP59tt3q2Fu6qsDR/QWDNxd1T/2CDs8W7ENVQzZS oRdTUWNOM/3MJvUywi6okmLMMQMySbNsa/V7xOlluc7TYr8QbzckTpdcFKQQVmmU gxFg6OrtUAfdaKftXDINlYsonVSPdJ46gCStYQ8D5DW/8Ug/HkSdbM85UOcUU8Ow 9+kAsNxeUBaykPoMQtJNtp6rd7pivhgb1T6TjGNlnY4EQ9j6iM/RhLFTKIApaDA8 scLftJs8PnCjufDEx3eE8/KtcWL75idfc0ImYgyPKHOzJFKBIxWHlPSutLP3z16r vW9pyE03/Ju4HSPCYiiL =r3i1 -----END PGP SIGNATURE-----
Current thread:
- CVE request: rpc-gssd is vulnerable to DNS spoofing Vincent Danen (Apr 03)
- Re: CVE request: rpc-gssd is vulnerable to DNS spoofing Kurt Seifried (Apr 04)