Debian DLA-345-1 : strongswan security update

2015-11-20T00:00:00
ID DEBIAN_DLA-345.NASL
Type nessus
Reporter This script is Copyright (C) 2015-2020 Tenable Network Security, Inc.
Modified 2015-11-20T00:00:00

Description

Tobias Brunner found an authentication bypass vulnerability in strongSwan, an IKE/IPsec suite.

Due to insufficient validation of its local state the server implementation of the EAP-MSCHAPv2 protocol in the eap-mschapv2 plugin can be tricked into successfully concluding the authentication without providing valid credentials.

It's possible to recognize such attacks by looking at the server logs. The following log message would be seen during the client authentication :

EAP method EAP_MSCHAPV2 succeeded, no MSK established

NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

                                        
                                            #%NASL_MIN_LEVEL 80502
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Debian Security Advisory DLA-345-1. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(86953);
  script_version("2.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/03/12");

  script_cve_id("CVE-2015-8023");

  script_name(english:"Debian DLA-345-1 : strongswan security update");
  script_summary(english:"Checks dpkg output for the updated packages.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Debian host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Tobias Brunner found an authentication bypass vulnerability in
strongSwan, an IKE/IPsec suite.

Due to insufficient validation of its local state the server
implementation of the EAP-MSCHAPv2 protocol in the eap-mschapv2 plugin
can be tricked into successfully concluding the authentication without
providing valid credentials.

It's possible to recognize such attacks by looking at the server logs.
The following log message would be seen during the client
authentication :

EAP method EAP_MSCHAPV2 succeeded, no MSK established

NOTE: Tenable Network Security has extracted the preceding description
block directly from the DLA security advisory. Tenable has attempted
to automatically clean and format it as much as possible without
introducing additional issues."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://lists.debian.org/debian-lts-announce/2015/11/msg00005.html"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/squeeze-lts/strongswan"
  );
  script_set_attribute(attribute:"solution", value:"Upgrade the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libstrongswan");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:strongswan");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:strongswan-dbg");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:strongswan-ikev1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:strongswan-ikev2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:strongswan-nm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:strongswan-starter");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:6.0");

  script_set_attribute(attribute:"patch_publication_date", value:"2015/11/19");
  script_set_attribute(attribute:"plugin_publication_date", value:"2015/11/20");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2015-2020 Tenable Network Security, Inc.");
  script_family(english:"Debian Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/Debian/release", "Host/Debian/dpkg-l");

  exit(0);
}


include("audit.inc");
include("debian_package.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/Debian/release")) audit(AUDIT_OS_NOT, "Debian");
if (!get_kb_item("Host/Debian/dpkg-l")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;
if (deb_check(release:"6.0", prefix:"libstrongswan", reference:"4.4.1-5.8")) flag++;
if (deb_check(release:"6.0", prefix:"strongswan", reference:"4.4.1-5.8")) flag++;
if (deb_check(release:"6.0", prefix:"strongswan-dbg", reference:"4.4.1-5.8")) flag++;
if (deb_check(release:"6.0", prefix:"strongswan-ikev1", reference:"4.4.1-5.8")) flag++;
if (deb_check(release:"6.0", prefix:"strongswan-ikev2", reference:"4.4.1-5.8")) flag++;
if (deb_check(release:"6.0", prefix:"strongswan-nm", reference:"4.4.1-5.8")) flag++;
if (deb_check(release:"6.0", prefix:"strongswan-starter", reference:"4.4.1-5.8")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:deb_report_get());
  else security_warning(0);
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");