This is an area I have been investigating for the past few months.  I think a 
network scanner is a good place to start and Nmap is a very strong network 
scanner.  An open port isn't a problem per se (SMTP port 25 or HTTP on port 80) 
since open ports are required for communication.  Nmap network scanner will 
indicate ports of interest and can do things like OS version discovery and use 
crafted scripts (written in LUA) to perform more sophisticated tests.

As far as whether the network is vulnerable, I'll give the tried and true "it 
depends".  As an example, I have crafted Nmap commands that will display status 
of z/OS ftp on port 21 with no z/OS userid required.  Is the machine vulnerable 
because anyone can know that JESINTERFACELEVEL=1?  Probably not, but if it is 
=2 that may raise my concern.  Vulnerability depends on security practices, 
system and app bugs, config settings, design, etc.  If ftp is tightly 
controlled with a strong configuration, good RACF rules and uses encryption 
(FTPS), then JESINTERFACELEVEL=2 may not concern you, but it probably would 
make me nervous.

Nessus, a popular vulnerability scanner, banner scrapes IBM HTTP Server V5.3 
and reports that the machine is "vulnerable" regardless of whether UK90649 has 
been APPLYed (Nessus plugin id 66760).  At least they tell you that in the 
description - Emily Litella practice.  There is an "exploit" written by Solider 
of Fortran in Metasploit that indicates issuing FILETYPE=JES and getting 
response=200 is a vulnerability.  Is it?  I don't think that is any more 
"vulnerable" than TSO SUBMIT.  I'm still bound to the userid I logged on with 
and if I can spawn a high authority shell (or TMP) or change my RACF 
attributes, that's the vulnerability to address.

I'm studying the Logica attack and it is hardcore.  The attackers got UID(0) on 
z/OS.  Machine "pwned", as the kids would say.  Traffic blended in with all 
other traffic and the attack was designed to be difficult to trace back to 
origin and to fly under the radar.  The attack was initially spotted on z/OS as 
an anomalous load, not on the network.  The vulnerabilities included lax 
firewall rules, bad RACF dataset and resource protection, loose policy on 
password strength, just to name a few factors.  It was a perfect target and the 
attackers were very talented and very sophisticated.

I like the SMTP vector mentioned here and will be incorporating that into my 
investigations.  Thanks ITschak! :-)

As a total aside, I just got back on IBM-MAIN today for the first time since 
... er ... a long time.  I was a heavy user of IBM-MAIN back in the early '90s 
before all of the swanky new interwebs.  I used to read Lionel in NaSPA's 
magazine back when that was still a thing.  I recognize a bunch of names and 
it's good to see they're still here.  :-)

Robyn

----

Robyn Gilchrist
RSH Consulting
r.gilchrist"at"rshconsulting.com <- replace "at" with @ to email me
www.linkedin.com/in/robyn-e-gilchrist

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