Vulnerabilities > CVE-2006-6302 - Remote Denial of Service vulnerability in Fail2Ban

047910
CVSS 5.0 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
PARTIAL
network
low complexity
fail2ban
nessus

Summary

fail2ban 0.7.4 and earlier does not properly parse sshd log files, which allows remote attackers to add arbitrary hosts to the /etc/hosts.deny file and cause a denial of service by adding arbitrary IP addresses to the sshd log file, as demonstrated by logging in via ssh with a login name containing certain strings with an IP address.

Nessus

NASL familyGentoo Local Security Checks
NASL idGENTOO_GLSA-200702-05.NASL
descriptionThe remote host is affected by the vulnerability described in GLSA-200702-05 (Fail2ban: Denial of Service) A flaw in the method used to parse log entries allows remote, unauthenticated attackers to forge authentication attempts from other hosts. Impact : A remote attacker can add arbitrary hosts to the block list, denying legitimate users access to a resource. Workaround : There is no known workaround at this time.
last seen2020-06-01
modified2020-06-02
plugin id24362
published2007-02-17
reporterThis script is Copyright (C) 2007-2019 Tenable Network Security, Inc.
sourcehttps://www.tenable.com/plugins/nessus/24362
titleGLSA-200702-05 : Fail2ban: Denial of Service
code
#%NASL_MIN_LEVEL 80502
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Gentoo Linux Security Advisory GLSA 200702-05.
#
# The advisory text is Copyright (C) 2001-2015 Gentoo Foundation, Inc.
# and licensed under the Creative Commons - Attribution / Share Alike 
# license. See http://creativecommons.org/licenses/by-sa/3.0/
#

include("compat.inc");

if (description)
{
  script_id(24362);
  script_version("1.13");
  script_cvs_date("Date: 2019/08/02 13:32:43");

  script_cve_id("CVE-2006-6302");
  script_xref(name:"GLSA", value:"200702-05");

  script_name(english:"GLSA-200702-05 : Fail2ban: Denial of Service");
  script_summary(english:"Checks for updated package(s) in /var/db/pkg");

  script_set_attribute(
    attribute:"synopsis", 
    value:
"The remote Gentoo host is missing one or more security-related
patches."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"The remote host is affected by the vulnerability described in GLSA-200702-05
(Fail2ban: Denial of Service)

    A flaw in the method used to parse log entries allows remote,
    unauthenticated attackers to forge authentication attempts from other
    hosts.
  
Impact :

    A remote attacker can add arbitrary hosts to the block list, denying
    legitimate users access to a resource.
  
Workaround :

    There is no known workaround at this time."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://security.gentoo.org/glsa/200702-05"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"All Fail2ban users should upgrade to the latest version:
    # emerge --sync
    # emerge --ask --oneshot --verbose '>=net-analyzer/fail2ban-0.6.2'"
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:gentoo:linux:fail2ban");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:gentoo:linux");

  script_set_attribute(attribute:"patch_publication_date", value:"2007/02/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2007/02/17");
  script_set_attribute(attribute:"vuln_publication_date", value:"2006/12/04");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2007-2019 Tenable Network Security, Inc.");
  script_family(english:"Gentoo Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/Gentoo/release", "Host/Gentoo/qpkg-list");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("qpkg.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/Gentoo/release")) audit(AUDIT_OS_NOT, "Gentoo");
if (!get_kb_item("Host/Gentoo/qpkg-list")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;

if (qpkg_check(package:"net-analyzer/fail2ban", unaffected:make_list("ge 0.6.2"), vulnerable:make_list("lt 0.6.2"))) flag++;

if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:qpkg_report_get());
  else security_warning(0);
  exit(0);
}
else
{
  tested = qpkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "Fail2ban");
}