Executive Summary

Summary
Title FUSE: incorrect filtering of environment variables leading to privilege escalation
Informations
Name GLSA-201603-04 First vendor Publication 2016-03-09
Vendor Gentoo Last vendor Modification 2016-03-09
Severity (Vendor) N/A Revision N/A

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score NA
Base Score NA Environmental Score NA
impact SubScore NA Temporal Score NA
Exploitabality Sub Score NA
 
Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector : (AV:L/AC:L/Au:N/C:N/I:P/A:P)
Cvss Base Score 3.6 Attack Range Local
Cvss Impact Score 4.9 Attack Complexity Low
Cvss Expoit Score 3.9 Authentication None Required
Calculate full CVSS 2.0 Vectors scores

Detail

Synopsis

The fusermount binary in FUSE does not properly clear the environment before invoking mount or umount as root that allows a local user to overwrite arbitrary files.

Background

FUSE provides an interface for filesystems implemented in userspace.

Description

The fusermount binary calls setuid(geteuid()) to reset the RUID when it invokes /bin/mount so that it can use privileged mount options that are normally restricted if RUID != EUID. FUSE does not properly clear environment variables before invoking mount or umount as root allowing this to be passed to operations using elevated privileges such as LIBMOUNT_MTAB that is used by the mount commands debugging feature.

Impact

The FUSE vulnerability allows a local, unprivileged user to overwrite arbitrary files on the system.

Workaround

There is no known work around at this time.

Resolution

All FUSE users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=sys-fs/fuse-2.9.4"

References

[ 1 ] CVE-2015-3202 : http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-3202

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website:

https://security.gentoo.org/glsa/201603-04

Original Source

Url : http://security.gentoo.org/glsa/glsa-201603-04.xml

CWE : Common Weakness Enumeration

% Id Name
100 % CWE-264 Permissions, Privileges, and Access Controls

CPE : Common Platform Enumeration

TypeDescriptionCount
Application 1
Os 1

Nessus® Vulnerability Scanner

Date Description
2017-02-21 Name : The remote Gentoo host is missing one or more security-related patches.
File : gentoo_GLSA-201702-10.nasl - Type : ACT_GATHER_INFO
2017-01-12 Name : The remote Gentoo host is missing one or more security-related patches.
File : gentoo_GLSA-201701-19.nasl - Type : ACT_GATHER_INFO
2016-03-10 Name : The remote Gentoo host is missing one or more security-related patches.
File : gentoo_GLSA-201603-04.nasl - Type : ACT_GATHER_INFO
2015-07-08 Name : The remote Amazon Linux AMI host is missing a security update.
File : ala_ALAS-2015-558.nasl - Type : ACT_GATHER_INFO
2015-06-15 Name : The remote SUSE host is missing one or more security updates.
File : suse_SU-2015-1053-1.nasl - Type : ACT_GATHER_INFO
2015-06-15 Name : The remote Fedora host is missing a security update.
File : fedora_2015-8782.nasl - Type : ACT_GATHER_INFO
2015-06-15 Name : The remote Fedora host is missing a security update.
File : fedora_2015-8777.nasl - Type : ACT_GATHER_INFO
2015-06-11 Name : The remote SUSE host is missing one or more security updates.
File : suse_SU-2015-1024-1.nasl - Type : ACT_GATHER_INFO
2015-06-10 Name : The remote Fedora host is missing a security update.
File : fedora_2015-8751.nasl - Type : ACT_GATHER_INFO
2015-06-09 Name : The remote Fedora host is missing a security update.
File : fedora_2015-8756.nasl - Type : ACT_GATHER_INFO
2015-06-09 Name : The remote Fedora host is missing a security update.
File : fedora_2015-8771.nasl - Type : ACT_GATHER_INFO
2015-06-09 Name : The remote Debian host is missing a security update.
File : debian_DLA-238.nasl - Type : ACT_GATHER_INFO
2015-06-08 Name : The remote openSUSE host is missing a security update.
File : openSUSE-2015-401.nasl - Type : ACT_GATHER_INFO
2015-06-04 Name : The remote openSUSE host is missing a security update.
File : openSUSE-2015-394.nasl - Type : ACT_GATHER_INFO
2015-06-02 Name : The remote Fedora host is missing a security update.
File : fedora_2015-8773.nasl - Type : ACT_GATHER_INFO
2015-05-27 Name : The remote Ubuntu host is missing a security-related patch.
File : ubuntu_USN-2617-3.nasl - Type : ACT_GATHER_INFO
2015-05-27 Name : The remote Debian host is missing a security update.
File : debian_DLA-226.nasl - Type : ACT_GATHER_INFO
2015-05-26 Name : The remote Ubuntu host is missing a security-related patch.
File : ubuntu_USN-2617-2.nasl - Type : ACT_GATHER_INFO
2015-05-26 Name : The remote Debian host is missing a security-related update.
File : debian_DSA-3268.nasl - Type : ACT_GATHER_INFO
2015-05-22 Name : The remote Debian host is missing a security-related update.
File : debian_DSA-3266.nasl - Type : ACT_GATHER_INFO
2015-05-22 Name : The remote Ubuntu host is missing a security-related patch.
File : ubuntu_USN-2617-1.nasl - Type : ACT_GATHER_INFO

Alert History

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Date Informations
2017-07-01 09:25:34
  • Multiple Updates
2017-02-22 13:21:09
  • Multiple Updates
2016-03-11 13:26:30
  • Multiple Updates
2016-03-09 21:29:19
  • Multiple Updates
2016-03-09 21:23:55
  • First insertion