Debian Security Advisory DSA 2826-1 (denyhosts - Remote denial of ssh service)

# OpenVAS Vulnerability Test
# $Id: deb_2826.nasl 6611 2017-07-07 12:07:20Z cfischer $
# Auto-generated from advisory DSA 2826-1 using nvtgen 1.0
# Script version: 1.0
#
# Author:
# Greenbone Networks
#
# Copyright:
# Copyright (c) 2013 Greenbone Networks GmbH http://greenbone.net
# Text descriptions are largely excerpted from the referenced
# advisory, and are Copyright (c) the respective author(s)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
#

include("revisions-lib.inc");

tag_affected  = "denyhosts on Debian Linux";
tag_insight   = "DenyHosts is a program that automatically blocks SSH
brute-force attacks by adding entries to /etc/hosts.deny.
It will also inform Linux administrators about offending
hosts, attacked users and suspicious logins.";
tag_solution  = "For the oldstable distribution (squeeze), this problem has been fixed in
version 2.6-7+deb6u2.

For the stable distribution (wheezy), this problem has been fixed in
version 2.6-10+deb7u2.

For the testing distribution (jessie), this problem has been fixed in
version 2.6-10.1.

For the unstable distribution (sid), this problem has been fixed in
version 2.6-10.1.

We recommend that you upgrade your denyhosts packages.";
tag_summary   = "Helmut Grohne discovered that denyhosts, a tool preventing SSH
brute-force attacks, could be used to perform remote denial of service
against the SSH daemon. Incorrectly specified regular expressions used
to detect brute force attacks in authentication logs could be exploited
by a malicious user to forge crafted login names in order to make
denyhosts ban arbitrary IP addresses.";
tag_vuldetect = "This check tests the installed software version using the apt package manager.";

if(description)
{
    script_id(702826);
    script_version("$Revision: 6611 $");
    script_cve_id("CVE-2013-6890");
    script_name("Debian Security Advisory DSA 2826-1 (denyhosts - Remote denial of ssh service)");
    script_tag(name: "last_modification", value:"$Date: 2017-07-07 14:07:20 +0200 (Fri, 07 Jul 2017) $");
    script_tag(name: "creation_date", value:"2013-12-22 00:00:00 +0100 (Sun, 22 Dec 2013)");
    script_tag(name: "cvss_base", value:"5.0");
    script_tag(name: "cvss_base_vector", value:"AV:N/AC:L/Au:N/C:N/I:N/A:P");

    script_xref(name: "URL", value: "http://www.debian.org/security/2013/dsa-2826.html");


    script_category(ACT_GATHER_INFO);

    script_copyright("Copyright (c) 2013 Greenbone Networks GmbH http://greenbone.net");
    script_family("Debian Local Security Checks");
    script_dependencies("gather-package-list.nasl");
    script_mandatory_keys("ssh/login/debian_linux", "ssh/login/packages");
    script_tag(name: "affected",  value: tag_affected);
    script_tag(name: "insight",   value: tag_insight);
#    script_tag(name: "impact",    value: tag_impact);
    script_tag(name: "solution",  value: tag_solution);
    script_tag(name: "summary",   value: tag_summary);
    script_tag(name: "vuldetect", value: tag_vuldetect);
    script_tag(name:"qod_type", value:"package");
    script_tag(name:"solution_type", value:"VendorFix");

    exit(0);
}

include("pkg-lib-deb.inc");

res = "";
report = "";
if ((res = isdpkgvuln(pkg:"denyhosts", ver:"2.6-7+deb6u2", rls:"DEB6.0")) != NULL) {
    report += res;
}
if ((res = isdpkgvuln(pkg:"denyhosts", ver:"2.6-10+deb7u2", rls:"DEB7.0")) != NULL) {
    report += res;
}

if (report != "") {
    security_message(data:report);
} else if (__pkg_match) {
    exit(99); # Not vulnerable.
}