> Does it really matter if an application vs z/OS has a trap door vulnerability?

Not if you don't care about security. If you care then you must investigate 
both. Please note that an unprivileged application can still have a dangerous 
back door that compromises, e.g., privacy, by giving a user authorized to 
access the application access more data than he is authorized to see.

> In either case z/OS and the ESM's cannot function
> properly when the TRAP DOOR vulnerability is exploited.

It can if you don't install the broken application.

> Shouldn't z/OS be able to protect itself from accidental and/or malicious 
> vulnerabilities? 

To quote Schiller, "Against stupidity the gods themselves contend in vain." The 
OS can prevent am unauthorized application from accessing unauthorized data or 
elevating its privileges; it cannot prevent the application from violating its 
own specifications. The OS also cannot protect against malicious modifications; 
it's a management responsibility to vet personnel and 3rd party providing OS 
changes and other privileged code. 

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

________________________________________
From: IBM Mainframe Discussion List <[email protected]> on behalf of Ray 
Overby <[email protected]>
Sent: Thursday, May 30, 2019 7:28 AM
To: [email protected]
Subject: Re: Fwd: Just how secure are mainframes? | Trevor Eddolls

In response to "An application with a trap door is an application
vulnerability. If there is a trap door in z/OS itself then that's a
platform vulnerability."

Does it really matter if an application vs z/OS has a trap door
vulnerability? In either case z/OS and the ESM's cannot function
properly when the TRAP DOOR vulnerability is exploited. Shouldn't z/OS
be able to protect itself from accidental and/or malicious
vulnerabilities? Isn't that what a platform is supposed to do? Isn't
that a requirement of a secure system?

Every program in z/OS has certain rules of the road it must abide by.
System level programs (PSW Key 0-7, Supervisor State, APF authorized)
regardless of whether they are in z/OS or an application have additional
rules they must adhere to (i.e. - they must not violate the integrity of
z/OS). These rules of the road are the responsibility of and dictated by
the platform. Integrity is a platform issue.

One of the reason's the mainframe is the most secure-able platform is at
least partially based on integrity. Integrity as implemented by the
platform is why security is possible. Without platform integrity
security is not possible. So all code (z/OS and application) that
operates at a system level (i.e. - PSW Key 0-7, Supervisor state, APF
authorized) must not violate the integrity rules. Failure of a single
program regardless of whether it is part of z/OS or an application will
allow a hacker to compromise that system and all data on it.

In response to "I'd be willing to bet a substantial amount that the
majority of penetrations in z/OS are application, configuration,
personnel and process vulnerabilities rather than z/OS vulnerabilities."

In terms of numbers of vulnerabilities there are fewer code based
vulnerabilities (TRAP DOOR is one example of a code based
vulnerabilities - there are others) vs configuration based
vulnerabilities. I would point out that a hacker only needs a single
TRAP DOOR  vulnerability to compromise the platform regardless of how
the platform is configured. So fewer code based vulnerabilities does not
help. All code based vulnerabilities have to be removed from the system
in order to secure the platform.

On 5/29/2019 2:57 PM, Seymour J Metz wrote:

>>   A single TRAP DOOR code vulnerability pierces the veil of integrity and 
>> can be used
>> to compromise the mainframe. Is this a platform weakness?
> An application with a trap door is an application vulnerability. If there is 
> a trap door in z/OS itself then that's a platform vulnerability. I'd be 
> willing to bet a substantial amount that the majority of penetrations in z/OS 
> are application, configuration, personnel and process vulnerabilities rather 
> than z/OS vulnerabilities.
>
>> Would you say that the elimination of User Key Common storage is an
>> example of a z/OS change to address a mainframe platform weakness
> Partially.
>
> --
> Shmuel (Seymour J.) Metz
> http://mason.gmu.edu/~smetz3
>
> ________________________________________
> From: IBM Mainframe Discussion List <[email protected]> on behalf of 
> Ray Overby <[email protected]>
> Sent: Wednesday, May 29, 2019 11:11 AM
> To: [email protected]
> Subject: Re: Fwd: Just how secure are mainframes? | Trevor Eddolls
>
> In response to "Mistakes, lack of time, lack of control, lack of skills.
> Not a platform weakness." comment: The mainframe platform, z/OS, and
> ESM's all rely on integrity to function. A single TRAP DOOR code
> vulnerability pierces the veil of integrity and can be used to
> compromise the mainframe. Is this a platform weakness? I think so. The
> platform relies on all code it runs adhering to certain rules. z/OS
> could be changed to better check and enforce those rules.
>
> Would you say that the elimination of User Key Common storage is an
> example of a z/OS change to address a mainframe platform weakness? I
> think so.
>
> An interesting observation. Thanks.
>
> On 5/29/2019 5:25 AM, R.S. wrote:
>> That's classical FUD.
>> Frightening people.
>> "if an exploit", "if job reads you RACF db", "unintended consequences".
>> What exactly hacking scenario can provide RACF db to the hacker?
>> Yes, I saw APF libraries with UACC(ALTER), UID(0) as standard TSO user
>> attribute, even UPDATE to RACF db. But it's problem of people.
>> Mistakes, lack of time, lack of control, lack of skills. Not a
>> platform weakness.
>>
>> It's typical that assurance/lock/gun salesmen tend to talk about
>> risks, threats and dangers. They create a vision.
>> My English is poor, but I can observe it for two of debaters here.
>> It's visible. I don't like social engineering.
>>
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