bugtraq - OpenBSD package 'net-snmp' information disclosure

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <CADxEXOhidL3ed9UKFoxSWdwwpLyhWmEg3vNqp3HG00DzM=ZCbA@mail.gmail.com>
Date: Thu, 12 Nov 2015 22:29:01 +0900
From: Pierre Kim <pierre.kim.sec@...il.com>
To: bugtraq@...urityfocus.com, fulldisclosure <fulldisclosure@...lists.org>
Subject: OpenBSD package 'net-snmp' information disclosure

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

## Advisory Information

Title: OpenBSD package 'net-snmp' information disclosure
Advisory URL: https://pierrekim.github.io/advisories/CVE-2015-8100-openbsd-net-snmp.txt
Blog URL: https://pierrekim.github.io/blog/2015-11-12-CVE-2015-8100-OpenBSD-package-net-snmp-information-disclosure.html
Date published: 2015-11-12
Vendors contacted: Stuart Henderson, OpenBSD Package maintainer
Release mode: Released
CVE: CVE-2015-8100

## Product Description

Net-SNMP is a suite of applications used to implement SNMP v1, SNMP v2c and
SNMP v3 using both IPv4 and IPv6.

This software is available in OpenBSD as a port (/usr/ports/net/net-snmp).

## Vulnerabilities Summary

By default, when OpenBSD package and ports are used, the snmpd
configuration file
has weak permissions which allows a local user to retrieve sensitive
information.

## Details

By default the permissions of the snmpd configuration file in OpenBSD
are 0644 instead of 0600:

  # cd /usr/ports/net/net-snmp
  # make install clean
  [...]
  # ls -latr /etc/snmp/snmpd.conf
  -rw-r--r--  1 root  wheel  6993 Nov  4 09:16 /etc/snmp/snmpd.conf
  #

The same problem occurs when the provided package is installed with
`pkg_add http://ftp.spline.de/pub/OpenBSD/5.8/packages/i386/net-snmp-5.7.3p0.tgz`:

  # ls -latr /etc/snmp/snmpd.conf
  -rw-r--r--  1 root  wheel  6993 Nov  4 08:37 /etc/snmp/snmpd.conf
  #

The snmpd configuration file is readable by a local user and contains
the credentials
for read-only and read-write access (for SNMPv1, SNMPv2 and SNMPv3
protocols) and
gives a local user unnecessary/dangerous access:

  [...]

  rocommunity public  default    -V systemonly
  #rocommunity secret  10.0.0.0/16
  rouser   authOnlyUser
  #rwuser   authPrivUser   priv

  [...]

This problem is OpenBSD-specific as the
/var/db/pkg/net-snmp-5.7.3p0/+CONTENTS file confirms:
  @ts 1438958635
  @sample /etc/snmp/snmpd.conf

Futhermore, by default, `/usr/local/sbin/snmpd` runs as root.

## Vendor Response

This problem has been fixed in the -STABLE and -CURRENT packages.

## Report Timeline

 * Nov 04, 2015: Vulnerability found by Pierre Kim.
 * Nov 06, 2015: Stuart Henderson is notified of the vulnerability.
 * Nov 06, 2015: Stuart Henderson confirms the vulnerability and fixes
the package permissions for the sample configuration file in -current
and -stable.
 * Nov 06, 2015: Stuart Henderson re-activates an option (can be
configured with rc.conf.local) to run net-snmp as a separate uid to
improve security.
 * Nov 10, 2015: OSS-Security is contacted to get a CVE
 * Nov 10, 2015: cve-assign@...re.org assigns CVE-2015-8100
 * Nov 12, 2015: A public advisory is sent to security mailing lists.

## Credit

This vulnerability was found by Pierre Kim (@PierreKimSec).

## References

https://pierrekim.github.io/advisories/CVE-2015-8100-openbsd-net-snmp.txt
http://openports.se/net/net-snmp

## Disclaimer

This advisory is licensed under a Creative Commons Attribution Non-Commercial
Share-Alike 3.0 License: http://creativecommons.org/licenses/by-nc-sa/3.0/

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
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=qkHs
-----END PGP SIGNATURE-----

-- 
Pierre Kim
pierre.kim.sec@...il.com
@PierreKimSec
https://pierrekim.github.io/