Fedora 26 : glibc (2018-8e27ad96ed) - Nessus

Critical Plugin ID: 106281

This page contains detailed information about the Fedora 26 : glibc (2018-8e27ad96ed) Nessus plugin including available exploits and PoCs found on GitHub, in Metasploit or Exploit-DB for verifying of this vulnerability.

Table Of Contents

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Plugin Overview
Vulnerability Information

Synopsis
Description
Solution

Public Exploits
Risk Information
Plugin Source
How to Run
References
Version

Plugin Overview

ID: 106281
Name: Fedora 26 : glibc (2018-8e27ad96ed)
Filename: fedora_2018-8e27ad96ed.nasl
Vulnerability Published: 2017-10-20
This Plugin Published: 2018-01-24
Last Modification Time: 2021-01-06
Plugin Version: 3.7
Plugin Type: local
Plugin Family: Fedora Local Security Checks
Dependencies: ssh_get_info.nasl
Required KB Items [?]: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list

Vulnerability Information

Severity: Critical
Vulnerability Published: 2017-10-20
Patch Published: 2018-01-23
CVE [?]: CVE-2017-15670, CVE-2017-15671, CVE-2017-15804, CVE-2017-16997, CVE-2018-1000001
CPE [?]: cpe:/o:fedoraproject:fedora:26, p-cpe:/a:fedoraproject:fedora:glibc

Synopsis

The remote Fedora host is missing a security update.

Description

This update addresses two security vulnerabilities :

- CVE-2017-15670, CVE-2017-15671, CVE-2017-15804: Various vulnerabilities could lead to memory corruption in the `glob` and `glob64` function. (RHBZ#1505298, RHBZ##1504807)

- CVE-2017-16997: Check for empty tokens before dynamic string token expansion in the dynamic linker, so that pre-existing privileged programs with `$ORIGIN` rpaths/runpaths do not cause the dynamic linker to search the current directory, potentially leading to privilege escalation. (RHBZ#1526866).

- CVE-2018-1000001: `getcwd` would sometimes return a non-absolute path, confusing the `realpath` function, leading to privilege escalation in conjunction with user namespaces. (RHBZ#1533837)

In addition, this update replaces the dynamic linker trampoline on x86-64 with a version which uses the `XSAVE` instruction if it is available. This improves compatibility with future hardware and compilers which do not follow the x86-64 ABI. This update also adjusts the thread stack size accounting to provide additional stack space compared to previous glibc versions (to avoid introducing RHBZ#1527887).

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Solution

Update the affected glibc package.

Public Exploits

Target Network Port(s): N/A
Target Asset(s): N/A
Exploit Available: True (Metasploit Framework, Exploit-DB, GitHub)
Exploit Ease: Exploits are available

Here's the list of publicly known exploits and PoCs for verifying the Fedora 26 : glibc (2018-8e27ad96ed) vulnerability:

Metasploit: exploit/linux/local/glibc_realpath_priv_esc
[glibc "realpath()" Privilege Escalation]
Metasploit: exploit/linux/local/glibc_realpath_priv_esc
[glibc 'realpath()' Privilege Escalation]
Exploit-DB: exploits/linux/local/44889.rb
[EDB-44889: glibc - 'realpath()' Privilege Escalation (Metasploit)]
GitHub: https://github.com/flyrev/security-scan-ci-presentation
[CVE-2017-15670]
GitHub: https://github.com/flyrev/security-scan-ci-presentation
[CVE-2017-15671]
GitHub: https://github.com/docker-library/faq
[CVE-2017-15804]
GitHub: https://github.com/flyrev/security-scan-ci-presentation
[CVE-2017-15804]
GitHub: https://github.com/ericcalabretta/inspec_resource_hab_pkg_deps
[CVE-2017-16997]
GitHub: https://github.com/flyrev/security-scan-ci-presentation
[CVE-2017-16997]
GitHub: https://github.com/Al1ex/LinuxEelvation
[CVE-2018-1000001]
GitHub: https://github.com/BaseMax/AwesomeCompiler
[CVE-2018-1000001]
GitHub: https://github.com/De4dCr0w/Linux-kernel-EoP-exp
[CVE-2018-1000001]
GitHub: https://github.com/R0B1NL1N/Linux-Kernal-Exploits-m-
[CVE-2018-1000001]
GitHub: https://github.com/Snoopy-Sec/Localroot-ALL-CVE
[CVE-2018-1000001]
GitHub: https://github.com/anoaghost/Localroot_Compile
[CVE-2018-1000001]
GitHub: https://github.com/flyrev/security-scan-ci-presentation
[CVE-2018-1000001]
GitHub: https://github.com/qiantu88/Linux--exp
[CVE-2018-1000001]
GitHub: https://github.com/rakjong/LinuxElevation
[CVE-2018-1000001]
GitHub: https://github.com/usernameid0/tools-for-CVE-2018-1000001
[CVE-2018-1000001: Tools for get offsets and adding patch for support i386]
GitHub: https://github.com/Xiami2012/CVE-2017-16997-poc
[CVE-2017-16997: A proof-of-concept for CVE-2017-16997]
GitHub: https://github.com/0x00-0x00/CVE-2018-1000001
[CVE-2018-1000001: Glibc getcwd() local privilege escalation compiled binaries]

Before running any exploit against any system, make sure you are authorized by the owner of the target system(s) to perform such activity. In any other case, this would be considered as an illegal activity.

WARNING: Beware of using unverified exploits from sources such as GitHub or Exploit-DB. These exploits and PoCs could contain malware. For more information, see how to use exploits safely.

Risk Information

CVSS V2 Vector [?]: AV:N/AC:M/Au:N/C:C/I:C/A:C/E:F/RL:OF/RC:C

CVSS Base Score:	9.3 (High)
Impact Subscore:	10.0
Exploitability Subscore:	8.6
CVSS Temporal Score:	7.7 (High)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	7.7 (High)

CVSS V3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

CVSS Base Score:	9.8 (Critical)
Impact Subscore:	5.9
Exploitability Subscore:	3.9
CVSS Temporal Score:	9.1 (Critical)
CVSS Environmental Score:	NA (None)
Modified Impact Subscore:	NA
Overall CVSS Score:	9.1 (Critical)

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Plugin Source

#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Fedora Security Advisory FEDORA-2018-8e27ad96ed.
#

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(106281);
  script_version("3.7");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/01/06");

  script_cve_id("CVE-2017-15670", "CVE-2017-15671", "CVE-2017-15804", "CVE-2017-16997", "CVE-2018-1000001");
  script_xref(name:"FEDORA", value:"2018-8e27ad96ed");

  script_name(english:"Fedora 26 : glibc (2018-8e27ad96ed)");
  script_summary(english:"Checks rpm output for the updated package.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Fedora host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"This update addresses two security vulnerabilities :

  - CVE-2017-15670, CVE-2017-15671, CVE-2017-15804: Various
    vulnerabilities could lead to memory corruption in the
    `glob` and `glob64` function. (RHBZ#1505298,
    RHBZ##1504807)

  - CVE-2017-16997: Check for empty tokens before dynamic
    string token expansion in the dynamic linker, so that
    pre-existing privileged programs with `$ORIGIN`
    rpaths/runpaths do not cause the dynamic linker to
    search the current directory, potentially leading to
    privilege escalation. (RHBZ#1526866).

  - CVE-2018-1000001: `getcwd` would sometimes return a
    non-absolute path, confusing the `realpath` function,
    leading to privilege escalation in conjunction with user
    namespaces. (RHBZ#1533837) 

In addition, this update replaces the dynamic linker trampoline on
x86-64 with a version which uses the `XSAVE` instruction if it is
available. This improves compatibility with future hardware and
compilers which do not follow the x86-64 ABI. This update also adjusts
the thread stack size accounting to provide additional stack space
compared to previous glibc versions (to avoid introducing
RHBZ#1527887).

Note that Tenable Network Security has extracted the preceding
description block directly from the Fedora update system website.
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://bodhi.fedoraproject.org/updates/FEDORA-2018-8e27ad96ed"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected glibc package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'glibc "realpath()" Privilege Escalation');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:glibc");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:26");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/10/20");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/01/23");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/01/24");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2018-2021 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Fedora Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/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);
release = get_kb_item("Host/RedHat/release");
if (isnull(release) || "Fedora" >!< release) audit(AUDIT_OS_NOT, "Fedora");
os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
os_ver = os_ver[1];
if (! preg(pattern:"^26([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 26", "Fedora " + os_ver);

if (!get_kb_item("Host/RedHat/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);


cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Fedora", cpu);


flag = 0;
if (rpm_check(release:"FC26", reference:"glibc-2.25-13.fc26")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "glibc");
}

The latest version of this script can be found in these locations depending on your platform:

Linux / Unix:
/opt/nessus/lib/nessus/plugins/fedora_2018-8e27ad96ed.nasl
Windows:
C:\ProgramData\Tenable\Nessus\nessus\plugins\fedora_2018-8e27ad96ed.nasl
Mac OS X:
/Library/Nessus/run/lib/nessus/plugins/fedora_2018-8e27ad96ed.nasl

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How to Run

Here is how to run the Fedora 26 : glibc (2018-8e27ad96ed) as a standalone plugin via the Nessus web user interface (https://localhost:8834/):

Click to start a New Scan.
Select Advanced Scan.
Navigate to the Plugins tab.
On the top right corner click to Disable All plugins.
On the left side table select Fedora Local Security Checks plugin family.
On the right side table select Fedora 26 : glibc (2018-8e27ad96ed) plugin ID 106281.
Specify the target on the Settings tab and click to Save the scan.
Run the scan.

Here are a few examples of how to run the plugin in the command line. Note that the examples below demonstrate the usage on the Linux / Unix platform.

Basic usage:

/opt/nessus/bin/nasl fedora_2018-8e27ad96ed.nasl -t <IP/HOST>

Run the plugin with audit trail message on the console:

/opt/nessus/bin/nasl -a fedora_2018-8e27ad96ed.nasl -t <IP/HOST>

Run the plugin with trace script execution written to the console (useful for debugging):

/opt/nessus/bin/nasl -T - fedora_2018-8e27ad96ed.nasl -t <IP/HOST>

Run the plugin with using a state file for the target and updating it (useful for running multiple plugins on the target):

/opt/nessus/bin/nasl -K /tmp/state fedora_2018-8e27ad96ed.nasl -t <IP/HOST>

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References

Fedora Security Update:

2018-8e27ad96ed

See also:

Similar and related Nessus plugins:

104292 - EulerOS 2.0 SP1 : glibc (EulerOS-SA-2017-1267)
104293 - EulerOS 2.0 SP2 : glibc (EulerOS-SA-2017-1268)
105814 - Fedora 27 : glibc (2017-0d3fdd3d1f)
106014 - Fedora 27 : glibc (2017-fb5e227432)
106041 - SUSE SLES12 Security Update : glibc (SUSE-SU-2018:0071-1)
106044 - SUSE SLED12 / SLES12 Security Update : glibc (SUSE-SU-2018:0074-1)
106045 - SUSE SLES11 Security Update : glibc (SUSE-SU-2018:0075-1)
106046 - SUSE SLES12 Security Update : glibc (SUSE-SU-2018:0076-1)
106059 - openSUSE Security Update : glibc (openSUSE-2018-30)
106134 - Ubuntu 14.04 LTS / 16.04 LTS / 17.10 : eglibc, glibc vulnerabilities (USN-3534-1)
106279 - Fedora 27 : glibc (2018-7714b514e2)
106775 - EulerOS 2.0 SP1 : glibc (EulerOS-SA-2018-1047)
106776 - EulerOS 2.0 SP2 : glibc (EulerOS-SA-2018-1048)
106865 - SUSE SLED12 / SLES12 Security Update : glibc (SUSE-SU-2018:0451-1)
106916 - openSUSE Security Update : glibc (openSUSE-2018-184)
107086 - SUSE SLES11 Security Update : glibc (SUSE-SU-2018:0565-1)
108822 - GLSA-201804-02 : glibc: Multiple vulnerabilities
108985 - RHEL 7 : glibc (RHSA-2018:0805)
109105 - Oracle Linux 7 : glibc (ELSA-2018-0805)
109371 - CentOS 7 : glibc (CESA-2018:0805)
109447 - Scientific Linux Security Update : glibc on SL7.x x86_64 (20180410)
109699 - Amazon Linux AMI : glibc (ALAS-2018-1017)
110603 - RHEL 6 : glibc (RHSA-2018:1879)
110648 - CentOS 6 : glibc (CESA-2018:1879)
110704 - Oracle Linux 6 : glibc (ELSA-2018-1879)
110884 - OracleVM 3.3 / 3.4 : glibc (OVMSA-2018-0235)
110886 - Scientific Linux Security Update : glibc on SL6.x i386/x86_64 (20180619)
111281 - Photon OS 2.0 : ruby / glibc (PhotonOS-PHSA-2018-2.0-0011-(a)) (deprecated)

Version

This page has been produced using Nessus Professional 10.1.2 (#68) LINUX, Plugin set 202205072148.
Plugin file fedora_2018-8e27ad96ed.nasl version 3.7. For more plugins, visit the Nessus Plugin Library.

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Fedora 26 : glibc (2018-8e27ad96ed) - Nessus

Plugin Overview

Vulnerability Information

Synopsis

Description

Solution

Public Exploits

Risk Information

Plugin Source

How to Run

References

Version

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