It's not the PTF that creates the exposure; it's the autorevocation policy, 
with or without the PTF.


--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3


________________________________________
From: IBM Mainframe Discussion List <[email protected]> on behalf of 
Peter Vander Woude <[email protected]>
Sent: Thursday, January 23, 2020 9:31 AM
To: [email protected]
Subject: Re: IBM AOAR O44855

The apar is meant to deal with those types of hacks, where someone has a list 
of userids and then just try to logon to TSO by connecting and attempting to 
logon to TSO.  Without the apar/parm, the normal logon screen shows the person 
IF the userid actually has a TSO profile.d

When the correct parm is in the IKJTSO00 parmlib member, they just get a prompt 
for the password.  There is no notification at that point that the user does, 
or does not, have TSO access.  Even the response does not tell the hacker that 
information.

While I agree that it could be a vein for a ddos of getting the users id 
revoked, the premise is valid to prevent the identification of someone with TSO 
access is very valid.

<<<<
Subject:


Re: IBM AOAR O44855

From: Seymour J Metz <[email protected]>
Reply-To: IBM Mainframe Discussion List <[email protected]>

Date: Tue, 21 Jan 2020 16:31:42 +0000

That opens the way to a denial of service attack; someone can write a script to 
cause revocation of a long list of userids.


--
Shmuel (Seymour J.) Metz

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