Vulnerabilities > CVE-2015-8107 - Use of Externally-Controlled Format String vulnerability in GNU A2Ps 4.14

047910
CVSS 6.8 - MEDIUM
Attack vector
NETWORK
Attack complexity
MEDIUM
Privileges required
NONE
Confidentiality impact
PARTIAL
Integrity impact
PARTIAL
Availability impact
PARTIAL
network
gnu
CWE-134
nessus

Summary

Format string vulnerability in GNU a2ps 4.14 allows remote attackers to execute arbitrary code.

Vulnerable Configurations

Part Description Count
Application
Gnu
1

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Format String Injection
    An attacker includes formatting characters in a string input field on the target application. Most applications assume that users will provide static text and may respond unpredictably to the presence of formatting character. For example, in certain functions of the C programming languages such as printf, the formatting character %s will print the contents of a memory location expecting this location to identify a string and the formatting character %n prints the number of DWORD written in the memory. An attacker can use this to read or write to memory locations or files, or simply to manipulate the value of the resulting text in unexpected ways. Reading or writing memory may result in program crashes and writing memory could result in the execution of arbitrary code if the attacker can write to the program stack.
  • String Format Overflow in syslog()
    This attack targets the format string vulnerabilities in the syslog() function. An attacker would typically inject malicious input in the format string parameter of the syslog function. This is a common problem, and many public vulnerabilities and associated exploits have been posted.

Nessus

NASL familyFreeBSD Local Security Checks
NASL idFREEBSD_PKG_E359051D90BD11E5BD18002590263BF5.NASL
descriptionJong-Gwon Kim reports : When user runs a2ps with malicious crafted pro(a2ps prologue) file, an attacker can execute arbitrary code.
last seen2020-06-01
modified2020-06-02
plugin id86999
published2015-11-23
reporterThis script is Copyright (C) 2015-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/86999
titleFreeBSD : a2ps -- format string vulnerability (e359051d-90bd-11e5-bd18-002590263bf5)
code
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from the FreeBSD VuXML database :
#
# Copyright 2003-2018 Jacques Vidrine and contributors
#
# Redistribution and use in source (VuXML) and 'compiled' forms (SGML,
# HTML, PDF, PostScript, RTF and so forth) with or without modification,
# are permitted provided that the following conditions are met:
# 1. Redistributions of source code (VuXML) must retain the above
#    copyright notice, this list of conditions and the following
#    disclaimer as the first lines of this file unmodified.
# 2. Redistributions in compiled form (transformed to other DTDs,
#    published online in any format, converted to PDF, PostScript,
#    RTF and other formats) must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer
#    in the documentation and/or other materials provided with the
#    distribution.
# 
# THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
# OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
# OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
# BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION,
# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

include("compat.inc");

if (description)
{
  script_id(86999);
  script_version("2.5");
  script_cvs_date("Date: 2018/11/23 12:49:57");

  script_cve_id("CVE-2015-8107");

  script_name(english:"FreeBSD : a2ps -- format string vulnerability (e359051d-90bd-11e5-bd18-002590263bf5)");
  script_summary(english:"Checks for updated package in pkg_info output");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote FreeBSD host is missing a security-related update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Jong-Gwon Kim reports :

When user runs a2ps with malicious crafted pro(a2ps prologue) file, an
attacker can execute arbitrary code."
  );
  # http://www.openwall.com/lists/oss-security/2015/11/16/4
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.openwall.com/lists/oss-security/2015/11/16/4"
  );
  # https://vuxml.freebsd.org/freebsd/e359051d-90bd-11e5-bd18-002590263bf5.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?c2771fb5"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:a2ps");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");

  script_set_attribute(attribute:"vuln_publication_date", value:"2015/11/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2015/11/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2015/11/23");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2015-2018 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"FreeBSD Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/FreeBSD/release", "Host/FreeBSD/pkg_info");

  exit(0);
}


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


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/FreeBSD/release")) audit(AUDIT_OS_NOT, "FreeBSD");
if (!get_kb_item("Host/FreeBSD/pkg_info")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;

if (pkg_test(save_report:TRUE, pkg:"a2ps<4.13b_8")) flag++;

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