Exim mail directory privilege escalation
|exim-mail-directory-priv-escalation (59043)||High Risk|
Exim could allow a local attacker to gain elevated privileges on the system, caused by an error when handling hardlinks in the mail directory during the mail delivery process. If the mail directory is world-writable with a sticky-bit set, a local attacker could exploit this vulnerability to create hard links to arbitrary files of another user.
Upgrade to the latest version of Exim (4.72 RC2 or later), available from the Exim Web site. See References.
- Exim Bugzilla Bug 988: CVE-2010-2023 - vulnerability with world-writable sticky mbox mail directory.
- Exim Web site: exim Internet Mailer.
- BID-40451: Exim Sticky Mail Directory Local Privilege Escalation Vulnerability
- CVE-2010-2023: transports/appendfile.c in Exim before 4.72, when a world-writable sticky-bit mail directory is used, does not verify the st_nlink field of mailbox files, which allows local users to cause a denial of service or possibly gain privileges by creating a hard link to another user's file.
- OSVDB ID: 65158: Exim transports/appendfile.c Hardlink Handling Arbitrary File Overwrite
- SA40019: exim Hardlink Handling and MBX Locking Two Weaknesses
- Cambridge University Exim 4.66
May 26, 2010
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The information within this database may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. In no event shall IBM be held liable for any damages whatsoever arising out of or in connection with the use or spread of this information.