Scientific Linux Security Update : sudo on SL5.x i386/x86_64
Medium Nessus Plugin ID 61456
SynopsisThe remote Scientific Linux host is missing a security update.
DescriptionAn insecure temporary file use flaw was found in the sudo package's post-uninstall script. A local attacker could possibly use this flaw to overwrite an arbitrary file via a symbolic link attack, or modify the contents of the '/etc/nsswitch.conf' file during the upgrade or removal of the sudo package. (CVE-2012-3440)
This update also fixes the following bugs :
- Previously, sudo escaped non-alphanumeric characters in commands using 'sudo -s' or 'sudo -' at the wrong place and interfered with the authorization process. Some valid commands were not permitted. Now, non-alphanumeric characters escape immediately before the command is executed and no longer interfere with the authorization process. (BZ#844418)
- Prior to this update, the sudo utility could, under certain circumstances, fail to receive the SIGCHLD signal when it was executed from a process that blocked the SIGCHLD signal. As a consequence, sudo could become suspended and fail to exit. This update modifies the signal process mask so that sudo can exit and sends the correct output. (BZ#844419)
- The sudo update RHSA-2012:0309 introduced a regression that caused the Security-Enhanced Linux (SELinux) context of the '/etc/nsswitch.conf' file to change during the installation or upgrade of the sudo package.
This could cause various services confined by SELinux to no longer be permitted to access the file. In reported cases, this issue prevented PostgreSQL and Postfix from starting. (BZ#842759)
- Updating the sudo package resulted in the 'sudoers' line in '/etc/nsswitch.conf' being removed. This update corrects the bug in the sudo package's post-uninstall script that caused this issue. (BZ#844420)
- Prior to this update, a race condition bug existed in sudo. When a program was executed with sudo, the program could possibly exit successfully before sudo started waiting for it. In this situation, the program would be left in a zombie state and sudo would wait for it endlessly, expecting it to still be running. (BZ#844978)
SolutionUpdate the affected sudo package.