[ISN] Gaping hole in NAI's Gauntlet firewall

From: InfoSec News (isnat_private)
Date: Tue Sep 04 2001 - 23:14:14 PDT

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    By Kevin Poulsen
    Experts are calling it a security manager's nightmare. For the second
    time in as many years, a hole has been discovered in Network
    Associate's Gauntlet firewall software that makes it possible for
    intruders to turn the security system against the very networks it was
    designed to protect, SecurityFocus has learned.
    On Tuesday, the company's PGP Security division quietly released
    patches for a buffer overflow vulnerability in the firewall's 'csmap'
    SMTP proxy, a feature of the firewall that, ironically, is designed to
    act as a protective membrane between an organization's mail server
    application and the rest of the world.
    In normal operation, csmap accepts mail connections from the Internet,
    then forwards only valid traffic to the internal mail server.
    By adding reams of text at a particular point in the mail transaction,
    an attacker can overflow the memory dedicated to storing an email
    address. Properly crafted computer instructions appended to the text
    will then be executed by the machine, giving hackers a way in.
    A spokesperson for Network Associates said the company could not
    immediately comment Tuesday. The bug affects users of Gauntlet 5.0,
    5.5 and 6.0 on Solaris and HP-UX, and the company's Web Shield line of
    The hole is the second serious security hole to be found in Gauntlet.
    Last year, Network Associates' integration of Mattel's Cyber Patrol
    filtering software into the product created another buffer overflow
    vulnerability that potentially gave attackers remote 'root' level
    access to the machine.
    The new vulnerability, like the last, was discovered by Jim Stickley,
    a San Diego-based computer security consultant with Garrison
    Technologies. Stickley uncovered the hole in July while performing a
    security audit for a Mississippi company that uses Gauntlet to protect
    its internal network.
    "Once you're on the firewall, you can go after any of the machines on
    the network," Stickley says. "The firewall is just a conduit at that
    Unlike the earlier hole, the new one doesn't yield total control of
    the compromised machine, says Stickley. But attackers have at their
    disposal a variety of means of gaining 'root' access to a typical Unix
    machine after penetrating at a lower level, says Stickley. With or
    without 'root,' the internal network is accessible.
    "Any time you hear of an exploit on the firewall that protects your
    internal network from public access, its kind of worrisome," says Jeff
    Haverlack, VP of information technology at a mid-sized financial
    institution. (Haverlack spoke on condition that the institution not be
    named). "If the Gauntlet is rendered useless through this exploit,
    we've got our online banking server sitting out there unprotected."
    But Haverlack still thinks well of Gauntlet, which commands a loyal
    following for its application-level architecture. The VP notes that
    buffer overflows are common in a variety of software products; A
    buffer overflow bug in Microsoft's IIS web server allowed the Code Red
    worm to spread around the world last July. "You're not going to be
    able to advance without leaving some holes behind you," Haverlack
    But some experts find security holes in security software to be
    particularly troubling.
    "I think we should be expecting more," says Chris Wysopal, director of
    research and development for security firm @Stake. A firewall is an
    absolutely critical part of any corporate security. This is the thing
    that keeps security professionals up at night.... Because unless
    you've put in multiple layers of security, which is a good idea, it's
    just opening the front door."
    Stickley agrees. "These aren't supposed to happen. That's ridiculous,
    that's amazing to me that they're letting these things go out the
    Network Associates had three percent of the $700 million firewall
    market in 2000, according to IDC.
    Gauntlet is not the only firewall to suffer security problems.
    Industry leader Checkpoint has had four vulnerabilities reported this
    year for its FireWall-1 product, though none of them yielded remote
    access to the machine itself.
    And last month Microsoft issued an advisory about its new ISA Server
    firewall, warning that under certain circumstances an attacker can
    slow down the system until it "deteriorate[s] to the point where it
    would effectively disrupt all communications across the firewall."
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