Home page logo

bugtraq logo Bugtraq mailing list archives

@(#)Mordred Labs advisory - Remote DoS in PostgreSQL <= 7.2.2
From: sir.mordred () hushmail com
Date: Wed, 12 Mar 2003 08:10:09 -0800


//@(#) Mordred Labs advisory 0x0007

Release date: August 26, 2002
Name: Remote DoS condition in PostgreSQL
Versions affected: <= 7.2.2
Conditions: entry in a pg_hba.conf file that matches attacker's host.
Risk: average
Author: Sir Mordred (http://mslabs.iwebland.com)

I. Description:

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
foreign keys, subqueries, triggers, user-defined types and functions.
Check http://www.postgresql.org for more information.

Upon connecting to a database, postmaster will fork a new process.
After that, a child process will call a
src/backend/postmaster/postmaster.c:DoBackend() routine,
which after processing a startup packet (see src/include/libpq/pqcomm.h),
will invoke a src/backend/libpq/auth.c:ClientAuthentication() routine to
perform client authentication.
If there is an entry in pg_hba.conf file, that matches an attacker's host,
an attacker could trigger
invocation of src/backend/libpq/auth.c:recv_and_check_password0(), which
fails to detect a DoS condition.

II. Details:
Consider this snip of code from src/backend/libpq/auth.c:

static int recv_and_check_password0(Port *port) {
        int32 len;
        char *buf;

        if (pq_getint(&len, 4) == EOF)
                return STATUS_EOF;
        len -= 4;
        buf = palloc(len); /* len is taken from a packet */

Note, that the size of palloced memory is taken from the user's input.

III. How to reproduce:

It's clear from the advisory how to reproduce this.

IV. Solution

Disable network access for untrusted users.

Version: Hush 2.2 (Java)
Note: This signature can be verified at https://www.hushtools.com/verify


Concerned about your privacy? Follow this link to get
FREE encrypted email: https://www.hushmail.com/?l=2 

Big $$$ to be made with the HushMail Affiliate Program: 

  By Date           By Thread  

Current thread:
  • @(#)Mordred Labs advisory - Remote DoS in PostgreSQL <= 7.2.2 sir . mordred (Mar 12)
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]