OSEC

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From: Loki (loki_at_fatelabs.com)
Date: Tue Aug 06 2002 - 14:30:55 CDT

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    ______________________________________________________________
                  Fate Research Laboratories
                      Security Advisory

    Package: Nullsoft SHOUTcast Server v1.8.9
    Vendor Web Site: http://www.shoutcast.com
    Versions: < = Latest (v1.8.9)
    Platforms: Windows, FreBSD, Linux, Mac, Solaris
    Advisory Title: DJ For a Day! Retrieving the SHOUTcast Admin
                        Password through GET /.
    Advisory ID: F820020731:SHOUT
    Issue Date: Thu Aug 1 11:24:12 EDT 2002
    File(s): sc_serv.log, sc_serv
    Local: Yes
    Remote: No
    Fix Available: No
    Vendor Contacted: Yes (08/03/2002)
    Researcher: Alan "ph33r" Neville <ph33rfatelabs.com>
    Fate Web Site: http://www.fatelabs.com
    _______________________________________________________________

    1. Overview

    There exists a flaw in the logging function for SHOUTcast,
    whereupon a GET request sent to port 8001 of the SHOUTcast
    server triggers the administrative password to be logged
    to a world readable logfile (sc_serv.log) located in the
    SHOUTcast directory. This attack requires a local user
    account to the machine. This attack is especially damaging
    to shared user environments such as web hosting companies
    that allow shell access to their users to a machine hosting
    the SHOUTcast server.

    2. Exploit

    Point a web browser at the SHOUTcast server port of (:8001)
    http://192.168.0.1:8001

    Other methods reproduced this exploit such as telnet and
    winamp directly with a simple GET request. Any TCP connection
    made to this port will fill the debug screen and log File
    with the cleartext password of the admin account.

    ----------------- debug log file ----------------------------

    -rw-r--r-- 1 ph33r ph33r 2364 Aug 2 03:20 sc_serv.log

    bash-2.05a$ tail -50 sc_serv.log

    <08/02/0203:20:01> [SHOUTcast] DNAS/FreeBSD4 v1.8.9
    (Mar 29 2002) starting up...
    <08/02/0203:20:01> [main] pid: 69400
    <08/02/0203:20:01> [main] loaded config from sc_serv.conf
    <08/02/0203:20:01> [main] initializing (usermax:32 portbase:8000)...
    <08/02/0203:20:01> [main] No ban file found (sc_serv.ban)
    <08/02/0203:20:01> [main] No rip file found (sc_serv.rip)
    <08/02/0203:20:01> [main] opening source socket
    <08/02/0203:20:01> [main] source thread starting
    <08/02/0203:20:02> [main] opening client socket
    <08/02/0203:20:02> [main] Client Stream thread [0] starting
    <08/02/0203:20:02> [main] client main thread starting
    <08/02/0203:20:02> [source] listening for connection on port 8001
    <08/02/0203:20:13> [source] invalid password from GET
    favicon.ico HTTP/1.1 changeme 192.168.0.2
    <08/02/0203:20:17> [source] invalid password from GET
    / HTTP/1.1 changeme 192.168.0.2
    <08/02/0203:20:17> [source] invalid password from GET
    / HTTP/1.1 changeme 192.168.0.2
    <08/02/0203:20:17> [source] invalid password from GET
    / HTTP/1.1 changeme 192.168.0.2
    <08/02/0203:20:23> [source] invalid password from GET
    / HTTP/1.1 changeme 192.168.0.2
    <08/02/0203:20:24> [source] invalid password from GET
    / HTTP/1.1 changeme 192.168.0.2
    <08/02/0203:20:25> [source] invalid password from GET
    / HTTP/1.1 changeme 192.168.0.2
    <08/02/0203:20:26> [source] invalid password from GET
    / HTTP/1.1 changeme 192.168.0.2

    /* changeme is the default password shipped with the
    SHOUTcast Server as seen above */

    ----------------- debug log file ----------------------------

    3. Impact

    The impact of this vulnerability can obviously be quite
    damaging. Lets take for instance that a malicious user decides
    to open up some "trial" web hosting accounts on several ISPs
    that he has identified as offering a SHOUTcast service from
    their machine. The user then opens up his free 30-day trial
    account and aims several GET requests to port 8001 of the machine
    where the SHOUTcast server is listening. The user than logs
    into the machine and locates the location of the SHOUTcast log file
    (sc_serv.log) using the locate or find command. Now, what makes
    this vulnreability possible is that SHOUTcast makes no warnings in their

    documentation that the log file by default is world readable.
    This obviously means that any user on the system can actually
    tail or cat the log file for the admin password. Repercussions
    obviously being complete administrative control of the SHOUTcast
    server.

    4. Vendor Response

    Nullsoft was contacted on 08/03/2002 whereupon Fate Labs pasted
    this Advisory to an email, while providing additional details on
    the Problem. Tom Pepper responded with quite dissidence. A
    statement from his email reads:

    "I fail to see how this constitutes a "critical problem".

    Well, unfortunately Nullsoft doesn't see this as an issue.
    Even going as far to say that the clear-text password being
    logged to the logfile was An "oft-request" made by SHOUTcast
    users. After debating the points made by Nullsoft in a followup
    email, no further responses were received. However, much to
    the credit of Nullsoft, a recommendation was made to enforce
    strict umodes on the SHOUTcast binary. It was their belief that
    if appropriate user access was used to start the Sc_serv binary,
    this wouldn't be an issue. We found this to be false.

    Following the instructions of the README file as well as
    starting the binary with a non-privileged user, we were in fact
    still able to reproduce the problem.

    5. Solution

    Until Nullsoft considers this to be an issue, we recommend the
    SHOUTcast admin ensures appropriate permissions on the logfile
    with a simple chmod 750. (chmod 750 sc_serv.log)

    (c) Copyright 1997-2002 Fate Research Labs. All Copyrights Reserved.
    Web: http://www.fatelabs.com