Title: EGI SVG 'ADVISORY' [TLP:WHITE] Up to 'CRITICAL' risk glibc
vulnerability CVE-2018-1000001 [EGI-SVG-CVE-2018-1000001]
Date: 2018-03-26
Updated: 2018-05-24
Affected software and risk
==========================
Up to CRITICAL risk vulnerability concerning glibc
Package : glibc
CVE ID : CVE-2018-1000001
In glibc 2.26 and earlier there is confusion in the usage of getcwd() by
realpath() which can be used to write before the destination buffer leading to
a buffer underflow and potential code execution. [R 1] [R 2]
For Ubuntu and Debian, there is a public exploit, [R 3] resulting in privilege
escalation to root.
The exploit needs adaptation to work under RHEL-based systems.
The exploit works primarily for hosts with unprivileged user name spaces
enabled, e.g. for use with singularity in non-setuid mode or docker.
Actions required/recommended
============================
**UPDATE 2018-05-24 **
Patches are now available for most relevant linux versions.
Sites typically should apply updates as soon as is convenient.
Sites with unprivileged user name spaces enabled should either apply the
relevant updates urgently, or apply the mitigation described below.
Affected software details
=========================
Affected: glibc 2.26 and earlier.
Fixed: glibc 2.27 [R 4].
More information
================
See [R 1], [R 2], [R 3], [R 4], [R 5], [R 7]
Mitigation
==========
Any site running singularity in non-setuid mode should consider changing to
setuid mode.
Similarly, sites using docker should consider running with unprivileged user
name spaces disabled.
Component installation information
==================================
**UPDATE 2018-05-24** - more versions of linux contain a fixed version of glibc
For RedHat Enterprise linux 7 see [R 5]
For Scientific Linux SL7 see [R 6]
For CentOS see [R 7]
**UPDATE 2018-05-24 after e-mail sent Correction**
Fixed in CentOS 7.5 released on 10th May.
For Ubuntu see [R 8]
For Debian see [R 9]
TLP and URL
===========
** WHITE information - Unlimited distribution
- see https://go.egi.eu/tlp for distribution restrictions **
URL: https://advisories.egi.eu/Advisory-SVG-CVE-2018-1000001
Minor updates may be made without re-distribution to the sites
Comments
========
Comments or questions should be sent to svg-rat at mailman.egi.eu
If you find or become aware of another vulnerability which is relevant to EGI
you may report it by e-mail to
report-vulnerability at egi.eu
the EGI Software Vulnerability Group will take a look according to the
procedure defined in [R 10]
Note that this has been updated and the latest version approved by the
Operations Management Board in November 2017
References
==========
[R 1] https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2018-1000001
[R 2] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-1000001.html
[R 3] https://www.exploit-db.com/exploits/43775/
[R 4] https://sourceware.org/ml/libc-announce/2018/msg00000.html
[R 5] https://access.redhat.com/security/cve/cve-2018-1000001
[R 6] https://www.scientificlinux.org/category/sl-errata/slsa-20180805-1/
[R 7] https://lists.centos.org/
[R 8] http://people.canonical.com/~ubuntu-security/cve/2018/CVE-2018-1000001.html
[R 9] https://security-tracker.debian.org/tracker/CVE-2018-1000001
[R 10] https://documents.egi.eu/public/ShowDocument?docid=3145
Credit
======
SVG was alerted to this vulnerability by Mischa Salle
Timeline
========
Yyyy-mm-dd [EGI-SVG-CVE-2018-1000001]
2018-02-20 SVG alerted to this issue by Mischa Salle from SVG
2018-02--- Various investigations and discussions on exploitability and risk
2018-03-21 Discussed at SVG meeting, agreed to draft 'Up to Critical' risk
advisory
2018-03-26 Advisory sent to sites
2018-05-24 Advisory updated as updates available for most relevant linux
versions and placed on wiki
Context
=======
This advisory has been prepared as part of the effort to fulfil EGI SVG's
purpose "To minimize the risk to the EGI infrastructure arising from software
vulnerabilities"
The risk is that assessed by the group, according to the EGI SVG issue handling
procedure [R 10] in the context of how the software is used in the EGI
infrastructure. It is the opinion of the group, we do not guarantee it to be
correct. The risk may also be higher or lower in other deployments depending on
how the software is used.
Others may re-use this information provided they:-
1) Respect the provided TLP classification
2) Credit the EGI https://www.egi.eu/ Software Vulnerability Group
On behalf of the EGI SVG,