Vulnerabilities > CVE-2012-6687 - Improper Input Validation vulnerability in Fastcgi Fcgi 2.4.0

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
fastcgi
CWE-20
nessus
NVD
Published: 2015-02-19
Updated: 2017-09-08

Summary

FastCGI (aka fcgi and libfcgi) 2.4.0 allows remote attackers to cause a denial of service (segmentation fault and crash) via a large number of connections.

Vulnerable Configurations

Part Description Count
Application
Fastcgi
1

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Server Side Include (SSI) Injection
    An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
  • Cross Zone Scripting
    An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
  • Cross Site Scripting through Log Files
    An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
  • Command Line Execution through SQL Injection
    An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.

Nessus

  • NASL familyMandriva Local Security Checks
    NASL idMANDRIVA_MDVSA-2015-226.NASL
    descriptionUpdated fcgi packages fix security vulnerability : FCGI does not perform range checks for file descriptors before use of the FD_SET macro. This FD_SET macro could allow for more than 1024 total file descriptors to be monitored in the closing state. This may allow remote attackers to cause a denial of service (stack memory corruption, and infinite loop or daemon crash) by opening many socket connections to the host and crashing the service (CVE-2012-6687).
    last seen2020-06-01
    modified2020-06-02
    plugin id83250
    published2015-05-05
    reporterThis script is Copyright (C) 2015-2019 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/83250
    titleMandriva Linux Security Advisory : fcgi (MDVSA-2015:226)
    code
    #%NASL_MIN_LEVEL 80502

#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Mandriva Linux Security Advisory MDVSA-2015:226. 
# The text itself is copyright (C) Mandriva S.A.
#

include("compat.inc");

if (description)
{
  script_id(83250);
  script_version("2.3");
  script_cvs_date("Date: 2019/08/02 13:32:57");

  script_cve_id("CVE-2012-6687");
  script_xref(name:"MDVSA", value:"2015:226");

  script_name(english:"Mandriva Linux Security Advisory : fcgi (MDVSA-2015:226)");
  script_summary(english:"Checks rpm output for the updated packages");

  script_set_attribute(
    attribute:"synopsis", 
    value:
"The remote Mandriva Linux host is missing one or more security
updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Updated fcgi packages fix security vulnerability :

FCGI does not perform range checks for file descriptors before use of
the FD_SET macro. This FD_SET macro could allow for more than 1024
total file descriptors to be monitored in the closing state. This may
allow remote attackers to cause a denial of service (stack memory
corruption, and infinite loop or daemon crash) by opening many socket
connections to the host and crashing the service (CVE-2012-6687)."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"http://advisories.mageia.org/MGASA-2015-0184.html"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"Update the affected fcgi, lib64fcgi0 and / or lib64fcgi0-devel
packages."
  );
  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:mandriva:linux:fcgi");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:mandriva:linux:lib64fcgi0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:mandriva:linux:lib64fcgi0-devel");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:mandriva:business_server:1");

  script_set_attribute(attribute:"patch_publication_date", value:"2015/05/04");
  script_set_attribute(attribute:"plugin_publication_date", value:"2015/05/05");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2015-2019 Tenable Network Security, Inc.");
  script_family(english:"Mandriva Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/cpu", "Host/Mandrake/release", "Host/Mandrake/rpm-list");

  exit(0);
}


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


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/Mandrake/release")) audit(AUDIT_OS_NOT, "Mandriva / Mandake Linux");
if (!get_kb_item("Host/Mandrake/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if (cpu !~ "^(amd64|i[3-6]86|x86_64)$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Mandriva / Mandrake Linux", cpu);


flag = 0;
if (rpm_check(release:"MDK-MBS1", cpu:"x86_64", reference:"fcgi-2.4.0-12.1.mbs1")) flag++;
if (rpm_check(release:"MDK-MBS1", cpu:"x86_64", reference:"lib64fcgi0-2.4.0-12.1.mbs1")) flag++;
if (rpm_check(release:"MDK-MBS1", cpu:"x86_64", reference:"lib64fcgi0-devel-2.4.0-12.1.mbs1")) flag++;


if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:rpm_report_get());
  else security_warning(0);
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");
  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DLA-430.NASL
    descriptionIt was discovered that there was a remote denial of service in libfcgi, a library for implementing the FastCGI web server protocol. For Debian 6 Squeeze, this issue has been fixed in libfcgi version 2.4.0-8+deb6u1. 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.
    last seen2020-03-17
    modified2016-02-26
    plugin id88971
    published2016-02-26
    reporterThis script is Copyright (C) 2016-2020 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/88971
    titleDebian DLA-430-1 : libfcgi security update
    code
    #%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-430-1. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(88971);
  script_version("2.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/03/12");

  script_cve_id("CVE-2012-6687");
  script_bugtraq_id(74454);

  script_name(english:"Debian DLA-430-1 : libfcgi 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:
"It was discovered that there was a remote denial of service in
libfcgi, a library for implementing the FastCGI web server protocol.

For Debian 6 Squeeze, this issue has been fixed in libfcgi version
2.4.0-8+deb6u1.

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/2016/02/msg00022.html"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/squeeze-lts/libfcgi"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Upgrade the affected libfcgi-dev, and libfcgi0ldbl packages."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  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:libfcgi-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libfcgi0ldbl");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:6.0");

  script_set_attribute(attribute:"patch_publication_date", value:"2016/02/25");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/02/26");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2016-2020 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:"libfcgi-dev", reference:"2.4.0-8+deb6u1")) flag++;
if (deb_check(release:"6.0", prefix:"libfcgi0ldbl", reference:"2.4.0-8+deb6u1")) 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");
  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DLA-431.NASL
    descriptionIt was discovered that there was a remote denial of service in libfcgi-perl, a helper library for implementing the FastCGI web server protocol for Perl. For Debian 6 Squeeze, this issue has been fixed in libfcgi-perl version 0.71-1+squeeze1+deb6u1. 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.
    last seen2020-03-17
    modified2016-02-26
    plugin id88972
    published2016-02-26
    reporterThis script is Copyright (C) 2016-2020 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/88972
    titleDebian DLA-431-1 : libfcgi-perl security update
    code
    #%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-431-1. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include("compat.inc");

if (description)
{
  script_id(88972);
  script_version("2.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/03/12");

  script_cve_id("CVE-2012-6687");
  script_bugtraq_id(74454);

  script_name(english:"Debian DLA-431-1 : libfcgi-perl security update");
  script_summary(english:"Checks dpkg output for the updated package.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Debian host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"It was discovered that there was a remote denial of service in
libfcgi-perl, a helper library for implementing the FastCGI web server
protocol for Perl.

For Debian 6 Squeeze, this issue has been fixed in libfcgi-perl
version 0.71-1+squeeze1+deb6u1.

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/2016/02/msg00023.html"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://packages.debian.org/source/squeeze-lts/libfcgi-perl"
  );
  script_set_attribute(
    attribute:"solution", 
    value:"Upgrade the affected libfcgi-perl package."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  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:libfcgi-perl");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:6.0");

  script_set_attribute(attribute:"patch_publication_date", value:"2016/02/25");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/02/26");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2016-2020 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:"libfcgi-perl", reference:"0.71-1+squeeze1+deb6u1")) 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");

References