EEYE: RealSecure/BlackICE Server Message Block (SMB) Processing Overflow

From: Marc Maiffret (mmaiffret_at_EEYE.COM)
Date: 02/27/04

  • Next message: George Starcher, CISSP: "Re: EEYE: RealSecure/BlackICE Server Message Block (SMB) Processing Overflow"
    Date:         Thu, 26 Feb 2004 18:36:18 -0800

    RealSecure/BlackICE Server Message Block (SMB) Processing Overflow

    Release Date:
    February 26, 2004

    Date Reported:
    February 18, 2004

    High (Remote Code Execution)

    Internet Security Systems

    Software Affected:
    RealSecure Network 7.0, XPU 20.15 through 22.9
    Real Secure Server Sensor 7.0 XPU 20.16 through 22.9
    Proventia A Series XPU 20.15 through 22.9
    Proventia G Series XPU 22.3 through 22.9
    Proventia M Series XPU 1.3 through 1.7
    RealSecure Desktop 7.0 eba through ebh
    RealSecure Desktop 3.6 ebr through ecb
    RealSecure Guard 3.6 ebr through ecb
    RealSecure Sentry 3.6 ebr through ecb
    BlackICE PC Protection 3.6 cbr through ccb
    BlackICE Server Protection 3.6 cbr through ccb

    The RealSecure and BlackICE product lines from Internet Security Systems
    offer host-based intrusion detection/prevention for large servers and
    home networks. By design, these products attempt to identify and block
    network attacks and intrusions.
    eEye Digital Security has discovered a critical vulnerability in both
    RealSecure and BlackICE. The vulnerability allows a remote attacker to
    reliably overwrite heap memory with user-controlled data and execute
    arbitrary code within the SYSTEM context. This attack will succeed with
    BlackICE using its most paranoid settings.

    This specific flaw exists within the component that handles the
    processing of Server Message Block (SMB) packets. By issuing an
    authentication request with a long username value, a direct heap
    overwrite is triggered, and reliable code execution is then possible.

    Technical Description:
    An IDS/IPS system, by its very nature, requires that every packet
    entering a system be parsed and dealt with accordingly. When BlackICE
    and RealSecure encounter an SMB packet, the packet is analyzed,
    processed and re-assembled. It is during this assembly phase that our
    custom data is passed to an insufficiently sized heap-based buffer. All
    processing is conducted before any authentication.

    To successfully replicate this vulnerability only one SMB packet is
    required. The client must issue an "SMB Session Setup AndX request".
    This SMB is used to "set up" a session previously established with the
    negotiate protocol. A primary function of this request is to perform a
    user login to a remote host. As neither RealSecure nor BlackICE require
    the state to be kept, no previous negotiation is required. To cause a
    reliable heap overwrite, the AccountName parameter should contain a
    string with a length of 300 bytes or greater.

    Please refer to the SNIA Common Internet File System Technical Reference
    ( for
    detailed information on the required packet structures.

    In the end, this vulnerability equates to a textbook heap overwrite
    vulnerability, and code execution is effortless.

    Retina Network Security Scanner has been updated to identify this

    Vendor Status:
    ISS have released patches for these issues. The patches are available

    Barnaby Jack

    Related Links:
    Retina Network Security Scanner - Free 15 Day Trial

    Cathy, The Filthy Few (we'll make up for it in July), and, of course --
    all of the eEye massive.

    Copyright (c) 1998-2004 eEye Digital Security
    Permission is hereby granted for the redistribution of this alert
    electronically. It is not to be edited in any way without express
    consent of eEye. If you wish to reprint the whole or any part of this
    alert in any other medium excluding electronic medium, please e-mail for permission.

    The information within this paper may change without notice. Use of this
    information constitutes acceptance for use in an AS IS condition. There
    are NO warranties with regard to this information. In no event shall the
    author be liable for any damages whatsoever arising out of or in
    connection with the use or spread of this information. Any use of this
    information is at the user's own risk.

    Please send suggestions, updates, and comments to:

    eEye Digital Security

    NTBugtraq Editor's Note:

    Most viruses these days use spoofed email addresses. As such, using an Anti-Virus product which automatically notifies the perceived sender of a message it believes is infected may well cause more harm than good. Someone who did not actually send you a virus may receive the notification and scramble their support staff to find an infection which never existed in the first place. Suggest such notifications be disabled by whomever is responsible for your AV, or at least that the idea is considered.

  • Next message: George Starcher, CISSP: "Re: EEYE: RealSecure/BlackICE Server Message Block (SMB) Processing Overflow"