Cis Apache 3.8

Ensure the Lock File Is Secured

Description

The LockFile directive sets the path to the lock file used when Apache uses fcntl(2) or flock(2) system calls to implement locking. Most Linux systems will default to using semaphores instead, so the directive may not apply. However, in the event a lock file is used, it is important for the lock file to be in a locally mounted directory that is not writable by other users.

Rationale

If the LockFile is placed in a writable directory, other accounts could create a denial of service attack and prevent the server from starting by creating a lock file with the same name.

Impact

None documented

Audit Procedure

Perform these steps to verify the lock file is secured properly:

1. Find the directory in which the LockFile would be created. The default value is the ServerRoot/logs directory.
2. Verify that the lock file directory is not a directory within the Apache DocumentRoot.
3. Verify that the lock file directory is on a locally mounted hard drive rather than an NFS mounted file system.
4. Verify that the ownership and group of the directory is root:root (or the user under which apache initially starts up if not root).
5. Verify that the permissions on the directory are only writable by root (or the startup user if not root).

Remediation

Perform these steps to properly secure the lock file:

1. Find the directory in which the LockFile would be created. The default value is the ServerRoot/logs directory.
2. Modify the directory for the LockFile so it is not within the Apache DocumentRoot and so it is on a locally mounted hard drive rather than an NFS mounted file system.
3. Change the ownership and group of the directory to be root:root.
4. Change the permissions on the directory so it is only writable by root, or the user under which apache initially starts up (default is root).

Default Value

The default lock file is logs/accept.lock.

References

1. https://httpd.apache.org/docs/2.2/mod/mpm_common.html#lockfile

CIS Controls

Version 6

18 Application Software Security

Application Software Security

Version 7

14.6 Protect Information through Access Control Lists

Protect all information stored on systems with file system, network share, claims, application, or database specific access control lists. These controls will enforce the principle that only authorized individuals should have access to the information based on their need to access the information as a part of their responsibilities.

Profile

Level 1 | Scored