Squid 3.x < 3.2.9 / 3.3.3 strHdrAcptLangGetItem Malformed Accept-Language Denial of Service

#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(65601);
  script_version("1.7");
  script_cvs_date("Date: 2019/11/27");

  script_cve_id("CVE-2013-1839");
  script_bugtraq_id(58316);

  script_name(english:"Squid 3.x < 3.2.9 / 3.3.3 strHdrAcptLangGetItem Malformed Accept-Language Denial of Service");
  script_summary(english:"Checks version of Squid");

  script_set_attribute(attribute:"synopsis", value:
"The remote proxy server is affected by a denial of service
vulnerability.");
  script_set_attribute(attribute:"description", value:
"According to its banner, the version of Squid running on the remote
host is 3.2.x prior to 3.2.9 or 3.3.x prior to 3.3.3 and is, therefore,
affected by a denial of service vulnerability.  An error exists in the
function 'strHdrAcptLangGetItem' in the file 'errorpage.cc' that could
allow certain 'Accept-Language' HTTP headers to cause a denial of
service condition. 

Note that Nessus has relied only on the version in the proxy server's
banner, which is not updated by the patch the project has released to
address the issue.  If this patch has been applied properly and the
service has been restarted, consider this to be a false positive.");
  script_set_attribute(attribute:"see_also", value:"http://www.squid-cache.org/Advisories/SQUID-2013_1.txt");
  script_set_attribute(attribute:"see_also", value:"https://seclists.org/bugtraq/2013/Mar/68");
  # http://www.squid-cache.org/Versions/v3/3.2/changesets/squid-3.2-11796.patch
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?bd6b7229");
  script_set_attribute(attribute:"solution", value:
"Either upgrade to Squid version 3.2.9 / 3.3.3 or later, or apply the
vendor-supplied patch.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2013-1839");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2013/03/05");
  script_set_attribute(attribute:"patch_publication_date", value:"2013/03/05");
  script_set_attribute(attribute:"plugin_publication_date", value:"2013/03/18");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:squid-cache:squid");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Firewalls");

  script_copyright(english:"This script is Copyright (C) 2013-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("squid_version.nasl");
  script_require_keys("www/squid", "Settings/ParanoidReport");
  script_require_ports("Services/http_proxy", 3128, 8080);

  exit(0);
}

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

# Build a list of ports from the
list = get_kb_list("http_proxy/*/squid/version");
if (isnull(list)) audit(AUDIT_NOT_INST, "Squid");

# nb: banner checks of open source software are prone to false-
#     positives so only run the check if reporting is paranoid.
if (report_paranoia < 2) audit(AUDIT_PARANOID);

vulnerable = FALSE;
not_vuln_list = make_list();

foreach item (keys(list))
{
  port = ereg_replace(pattern:'^http_proxy/([0-9]+)/squid/version', replace:'\\1', string:item);
  version = list[item];
  # Affected:
  # Squid 3.2 < 3.2.9
  # Squid 3.3.0.x < 3.3.3
  if (
    version =~ "^3\.2\.[0-8]([^0-9]|$)" ||
    version =~ "^3\.3\.[0-2]([^0-9]|$)"
  )
  {
    vulnerable = TRUE;
    if (report_verbosity > 0)
    {
      source = get_kb_item('http_proxy/'+port+'/squid/source');
      report =
        '\n  Version source    : ' + source +
        '\n  Installed version : ' + version +
        '\n  Fixed version     : 3.2.9 / 3.3.3' + '\n';
      security_hole(port:port, extra:report);
    }
    else security_hole(port:port);
  }
  else not_vuln_list = make_list(not_vuln_list, version + " on port " + port);
}

if (vulnerable) exit(0);
else
{
  installs = max_index(not_vuln_list);
  if (installs == 0) audit(AUDIT_NOT_INST, "Squid");
  else if (installs == 1)
    audit(AUDIT_INST_VER_NOT_VULN, "Squid", not_vuln_list[0]);
  else
    exit(0, "The Squid installs ("+ join(not_vuln_list, sep:", ") + ") are not affected.");
}