Insecure Temporary File Creation In MySQL — GLSA 200405-20

Two MySQL utilities create temporary files with hardcoded paths, allowing an attacker to use a symlink to trick MySQL into overwriting important data.

Affected packages

Package 	dev-db/mysql on all architectures
Affected versions 	< 4.0.18-r2
Unaffected versions 	>= 4.0.18-r2

Background

MySQL is a popular open-source multi-threaded, multi-user SQL database server.

Description

The MySQL bug reporting utility (mysqlbug) creates a temporary file to log bug reports to. A malicious local user with write access to the /tmp directory could create a symbolic link of the name mysqlbug-N pointing to a protected file, such as /etc/passwd, such that when mysqlbug creates the Nth log file, it would end up overwriting the target file. A similar vulnerability exists with the mysql_multi utility, which creates a temporary file called mysql_multi.log.

Impact

Since mysql_multi runs as root, a local attacker could use this to destroy any other users' data or corrupt and destroy system files.

Workaround

One could modify both scripts to log to a directory that users do not have write permission to, such as /var/log/mysql/.

Resolution

All users should upgrade to the latest stable version of MySQL.

 # emerge sync

 # emerge -pv ">=dev-db/mysql-4.0.18-r2"
 # emerge ">=dev-db/mysql-4.0.18-r2"

References

    CAN-2004-0381
    CAN-2004-0388