/ 
Apache-Session-1.94
/ Apache::Session::Lock::File
Security Advisories (3)
CVE-2013-10075 (2026-05-08)

Apache::Session versions through 1.94 for Perl re-creates deleted sessions. The session stores Apache::Session::Store::File and Apache::Session::Store::DB_File will create a session that does not exist. This can lead to sessions being revived, potentially with data that was to be deleted.

CVE-2025-40931 (2026-03-05)

Apache::Session::Generate::MD5 versions through 1.94 for Perl create insecure session id. Apache::Session::Generate::MD5 generates session ids insecurely. The default session id generator returns a MD5 hash seeded with the built-in rand() function, the epoch time, and the PID. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand function is unsuitable for cryptographic usage. Predicable session ids could allow an attacker to gain access to systems. Note that the libapache-session-perl package in some Debian-based Linux distributions may be patched to use Crypt::URandom.

CVE-2026-5081 (2026-05-06)

Apache::Session::Generate::ModUniqueId versions from 1.54 through 1.94 for Perl session ids are insecure. Apache::Session::Generate::ModUniqueId (added in version 1.54) uses the value of the UNIQUE_ID environment variable for the session id. The UNIQUE_ID variable is set by the Apache mod_unique_id plugin, which generates unique ids for the request. The id is based on the IPv4 address, the process id, the epoch time, a 16-bit counter and a thread index, with no obfuscation. The server IP is often available to the public, and if not available, can be guessed from previous session ids being issued. The process ids may also be guessed from previous session ids. The timestamp is easily guessed (and leaked in the HTTP Date response header). The purpose of mod_unique_id is to assign a unique id to requests so that events can be correlated in different logs. The id is not designed, nor is it suitable for security purposes.

NAME

Apache::Session::Lock::File - Provides mutual exclusion using flock

SYNOPSIS

use Apache::Session::Lock::File;

my $locker = Apache::Session::Lock::File->new;

$locker->acquire_read_lock($ref);
$locker->acquire_write_lock($ref);
$locker->release_read_lock($ref);
$locker->release_write_lock($ref);
$locker->release_all_locks($ref);

$locker->clean($dir, $age);

DESCRIPTION

Apache::Session::Lock::File fulfills the locking interface of Apache::Session. Mutual exclusion is achieved through the use of temporary files and the flock function.

CONFIGURATION

The module must know where to create its temporary files. You must pass an argument in the usual Apache::Session style. The name of the argument is LockDirectory and its value is the path where you want the lockfiles created. Example:

tie %s, 'Apache::Session::Blah', $id, {LockDirectory => '/var/lock/sessions'}

If you do not supply this argument, temporary files will be created in /tmp.

NOTES

clean

This module does not unlink temporary files, because it interferes with proper locking. This can cause problems on certain systems (Linux) whose file systems (ext2) do not perform well with lots of files in one directory. To prevent this you should use a script to clean out old files from your lock directory. The meaning of old is left as a policy decision for the implementor, but a method is provided for implementing that policy. You can use the clean method of this module to remove files unmodified in the last $age seconds. Example:

my $l = Apache::Session::Lock::File->new;
$l->clean('/var/lock/sessions', 3600) #remove files older than 1 hour

acquire_read_lock

Will do nothing if write lock is in effect, only set readlock flag to true.

release_read_lock

Will do nothing if write lock is in effect, only set readlock flag to false.

Win32 and Cygwin

Windows cannot escalate lock, so all locks will be exclusive.

release_read_lock not supported - it is not used by Apache::Session.

When deleting files, they are not locked (Win32 only).

AUTHOR

This module was written by Jeffrey William Baker <jwbaker@acm.org>.

SEE ALSO

Apache::Session