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Home » Security Advisories» FreeBSD » Mod_auth_pgsql port authentication bypass

Mod_auth_pgsql port authentication bypass

The mod_auth_pgsql port, versions prior to mod_auth_pgsql-0.9.9, contain a vulnerability that may allow a remote user to cause arbitrary SQL code to be execute.

  • Vendor: FreeBSD
  • Vendor ID: SA-02:03
  • Date: January 04, 2002


FreeBSD-SA-02:03 Security Advisory
FreeBSD, Inc.

Topic: mod_auth_pgsql port authentication bypass

Category: ports
Module: mod_auth_pgsql
Announced: 2002-01-04
Credits: RUS CERT
Affects: Ports collection prior to the correction date
Corrected: 2001-10-02 11:33:49 UTC
FreeBSD only: NO

I. Background

mod_auth_pgsql is an Apache module which allows the Apache web server
to use a PostgreSQL database for user and/or group authentication.

II. Problem Description

The mod_auth_pgsql port, versions prior to mod_auth_pgsql-0.9.9,
contain a vulnerability that may allow a remote user to cause
arbitrary SQL code to be execute. mod_auth_pgsql constructs a SQL
statement to be executed by the PostgreSQL server in order to lookup
user information. The username given by the remote user is inserted
into the SQL statement without any quoting or other safety checks.

The mod_auth_pgsql port is not installed by default, nor is it "part of
FreeBSD" as such: it is part of the FreeBSD ports collection, which
contains over 6000 third-party applications in a ready-to-install
format. The ports collection shipped with FreeBSD 4.4 contains this
problem since it was discovered after the release.

FreeBSD makes no claim about the security of these third-party
applications, although an effort is underway to provide a security
audit of the most security-critical ports.

III. Impact

A remote user may insert arbitrary SQL code into the username during
authentication, leading to several exploit opportunities. In
particular, the attacker may cause mod_auth_pgsql to use a known fixed
password hash for user verification, allowing him to authenticate as
any user and obtain unauthorized access to web server data.

IV. Workaround

1) Deinstall the mod_auth_pgsql port/package if you have it installed.

V. Solution

1) Upgrade your entire ports collection and rebuild the port.

2) Deinstall the old package and install a new package dated after the
correction date, obtained from the following directories:


Packages are not automatically generated for the alpha architecture at
this time due to lack of build resources.

3) Download a new port skeleton for the mod_auth_pgsql port from:

and use it to rebuild the port.

4) Use the portcheckout utility to automate option (3) above. The
portcheckout port is available in /usr/ports/devel/portcheckout or the
package can be obtained from:

VI. Correction details

The following list contains the $FreeBSD$ revision numbers of each
file that was corrected in the FreeBSD source

Path Revision
- -------------------------------------------------------------------------
ports/www/mod_auth_pgsql/Makefile 1.3
ports/www/mod_auth_pgsql/distinfo 1.2
- -------------------------------------------------------------------------

VII. References

Version: GnuPG v1.0.6 (FreeBSD)
Comment: For info see


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