NGS000267 Technical Advisory: Symantec Messaging Gateway SSH with backdoor user account plus privilege escalation to root due to very old Kernel

[NCC Group Research <research () nccgroup com>]

=======
Summary
=======
Name: Symantec Messaging Gateway - SSH with backdoor user account + privilege escalation to root due to very old Kernel
Release Date: 30 November 2012
Reference: NGS00267
Discoverer: Ben Williams <ben.williams () ngssecure com>
Vendor: Symantec
Vendor Reference: 
Systems Affected: Symantec Messaging Gateway 9.5.3-3
Risk: High
Status: Published

========
TimeLine
========
Discovered: 18 April 2012
Released: 18 April 2012
Approved: 29 April 2012
Reported: 30 April 2012
Fixed: 27 August 2012
Published: 30 November 2012

===========
Description
===========
I. VULNERABILITY
-------------------------
Symantec Messaging Gateway 9.5.3-3 - SSH with backdoor user account + privilege escalation to root due to very old 
Kernel

II. BACKGROUND
-------------------------
Symantec Messaging Gateway 9.5.3-3 is the latest version, of their Email Security Appliance

III. DESCRIPTION
-------------------------
The "admin" SSH account has a restricted shell, and the password is set by the administrator during setup.

However, there is another SSH account "support" which has a default password, which is not changed during installation, 
and does not seem to be mentioned in the Symantec documentation as far as I can see (Installation Guide, Administration 
Guide or Command-line Guide). This account has a very easy-to-guess password, but many administrators may not know it 
exists.

Additionally, the Linux Kernel on the appliance has not been updated since late 2007 (almost 5 years) so suffers from 
multiple privilege escalation issues (as do other old packages on the operating system) so if SSH is accessible to an 
attacker, it is possible for them to login and escalate to root.

=================
Technical Details
=================
IV. PROOF OF CONCEPT
-------------------------
Both the install wizard and the documentation prompt the administrator to change the password for the "admin" account, 
for both the UI and for SSH to the operating system. This admin account can SSH in to the appliance, with the new 
chosen password, and has a restricted shell environment where only certain application administration commands are 
possible. 

It is not possible to login as root. However, there is another account "support" which has a default password of 
"symantec" which is not mentioned anywhere in the installer or documentation (as far as I can see) and the password is 
not changed as part of the installation process. This account is able to login to the OS via SSH, and does not have a 
restricted shell environment.

Additionally, the Linux Kernel is very old (2007) so suffers from multiple privilege escalation issues.

[+] Results for kernel version 2.6.18-274.3.1.2.el5_sms

Potential exploits:

* Linux Kernel BCM Local Root Exploit
    CVE: CVE-2010-2959
    Affects kernels: 2.6.0-2.6.36rc1
    Exploits:
    http://www.exploit-db.com/exploits/14814

* Linux Kernel RDS protocol Local Root Exploit
    CVE: CVE-2010-3904
    Affects kernels: 2.6.0-2.6.36rc8
    Exploits:
    http://www.exploit-db.com/exploits/15285

* Linux Kernel econet_sendmsg() - half-nelson Local Root Exploit
    CVE: CVE-2010-3848                                                 
    Affects kernels: 2.6.0-2.6.36.2                                        
    Exploits:                                                              
    http://www.exploit-db.com/exploits/17787                             
                   
* Linux Kernel Unknown Local Root Exploit                                  
    CVE: CVE-None                                                          
    Affects kernels: 2.6.18-2.6.20
    Exploits:
    http://www.exploit-db.com/exploits/10613

* Linux Kernel sock_sendpage() (Wunderbar Emporium) Local Root Exploit
    CVE: CVE-2009-2692
    Affects kernels: 2.6.0-2.6.31rc3
    Exploits:
    http://www.exploit-db.com/exploits/9641
    http://www.exploit-db.com/exploits/9545
    http://www.exploit-db.com/exploits/9479
    http://www.exploit-db.com/exploits/9436
    http://www.exploit-db.com/exploits/9435
    http://www.grsecurity.net/~spender/enlightenment.tgz

* Linux Kernel pipe.c (MooseCox) Local Root Exploit
    CVE: CVE-2009-3547
    Affects kernels: 2.6.0-2.6.32rc5
    Exploits:
    http://www.exploit-db.com/exploits/10018
    http://www.grsecurity.net/~spender/enlightenment.tgz

* Linux Kernel ReiserFS xattr Local Root Exploit
    CVE: CVE-2010-1146
    Affects kernels: 2.6.0-2.6.34rc3
    Exploits:
    http://www.exploit-db.com/exploits/12130

* Linux Kernel vmsplice Local Root Exploit
    CVE: CVE-2008-0009
    Affects kernels: 2.6.17-2.6.24.1
    Exploits:
    http://www.exploit-db.com/exploits/5092
    http://www.exploit-db.com/exploits/5093

* Linux Kernel ec_dev_ioctl() - half-nelson Local Root Exploit
    CVE: CVE-2010-3850
    Affects kernels: 2.6.0-2.6.36.2
    Exploits:
    http://www.exploit-db.com/exploits/17787
    http://www.exploit-db.com/exploits/15704

* Linux Kernel ACPI custom_method Local Root Exploit
    CVE: CVE-2010-4347
    Affects kernels: 2.6.0-2.6.37rc2
    Exploits:
    http://www.exploit-db.com/exploits/15774

* Linux Kernel ftruncate()/open() Local Root Exploit
    CVE: CVE-2008-4210
    Affects kernels: 2.6.0-2.6.22
    Exploits:
    http://www.exploit-db.com/exploits/6851

* Linux Kernel put_user() - full-nelson Local Root Exploit
    CVE: CVE-2010-4258
    Affects kernels: 2.6.0-2.6.37
    Exploits:
    http://www.exploit-db.com/exploits/15704

* Linux Kernel sock_no_sendpage() - full-nelson Local Root Exploit
    CVE: CVE-2010-3849
    Affects kernels: 2.6.0-2.6.37
    Exploits:
    http://www.exploit-db.com/exploits/15704

* Linux Kernel ipc - half-nelson Local Root Exploit
    CVE: CVE-2010-4073
    Affects kernels: 2.6.0-2.6.37rc1
    Exploits:
    http://www.exploit-db.com/exploits/17787

* Linux Kernel SELinux/RHEL5 (Cheddar Bay) Local Root Exploit
    CVE: CVE-None
    Affects kernels: 2.6.9-2.6.30
    Exploits:
    http://www.exploit-db.com/exploits/9208
    http://www.exploit-db.com/exploits/9191
    http://www.grsecurity.net/~spender/enlightenment.tgz

* Linux Kernel exit_notify() Local Root Exploit
    CVE: CVE-2009-1337
    Affects kernels: 2.6.0-2.6.29
    Exploits:
    http://www.exploit-db.com/exploits/8369

* Linux Kernel system call emulation Local Root Exploit
    CVE: CVE-2007-4573
    Affects kernels: 2.6.0-2.6.22.7
    Exploits:
    http://www.exploit-db.com/exploits/4460

* Linux Kernel set_selection() UTF-8 Off By One Local Root Exploit
    CVE: CVE-2009-1046
    Affects kernels: 2.6.0-2.6.28.3
    Exploits:
    http://www.exploit-db.com/exploits/9083

===============
Fix Information
===============

An updated version of the software has been released to address the vulnerability:
http://www.symantec.com/security_response/securityupdates/detail.jsp?fid=security_advisory&pvid=security_advisory&year=2012&suid=20120827_00

NCC Group Research
http://www.nccgroup.com/research


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