ISA Healthcheck

1) What should/would/do external or internal IT auditors or security professionals look at when reviewing the configuration and management of a corporate ISA server? Could you provde some examples of essential things that should be looked at, common mistakes admins make, common issues found through "set it and forget it" type configs...

2) What sort of things would indicate a poorly configured/managed ISA server, please provide some practical examples for a manager/low tech, with subsequent risks....
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ChrisConnect With a Mentor Commented:
depends how your ISA is used and setup
i.e. is it only out going as a User proxy
or is it used a reverse proxy
then is it externally facing or behind another firewall

Simple scenario - if behind another firewall and only used for user proxy and then a rule check to ensure there are no inbound rules and the outbound is only those required i.e. HTTP, HTTPS, FTP
Then a rule base check and permissions check (which users have access to which rules) which depends on your HR/Fair usage policy as to how through you are to ensure people can get to what they need to and anything else is blocked

Less simple
externally facing but only used for user proxy - a Penetration test would be appropriate, probably as part of a full external test along  with the checks above

Complicated - behind another firewall bit with both inbound and outbound rules
Along with the rule check on the ISA for outbound access a rule check for inbound and a Pen Test for all externally accessible services

then the final scenario is externally presented and both inbound and outbound rules - this would be the same as the check above
Common mistakes
User Proxy (outbound)
fairly open rules i.e. Any<>Any style rules meaning any users can get to and from any destinations
use of individuals instead of groups to allow access to rules
combining rules where additional rules should be used, allow access to additional sites.

All these come from initial setup or poor change control, making sure this is all documented with what rules should be on there and standards for creating rules will help avoid these situations

The risk is that users can get to sites that they should be allowed to get to from a corporate stance i.e. facebook, twitter etc
they can get to sites that will damage the company or its infrastructure i.e. downloading malware, viruses etc

Risks for outbound rules is that internally services are presented to users that should have access to them i.e. hackers that could gain access to your network.
this is either through incorrectly configured rules or by poor patching which leaves systems with vulnerabilities
pma111Author Commented:
Thank you:

>>combining rules where additional rules should be used, allow access to additional sites.
>>use of individuals instead of groups to allow access to rules

Can you elaborate on these a little?
rule 1 - allows Group 1 access to Website list 1

you amend the rule to allow group 1 access to website list 2

someone then asks to have access to website list 1 but doesn't/shouldn't need access to webste list 2

they are just added into rule 1 instead of creating rule 2
which would be - rule 2 allowings group 2 access to website list 1
balmasriConnect With a Mentor Commented:
usually check the following:
-Administrative roles/permissions over the server , Array.
-Unnecessary Rules  like allow outbound any protocols.
-localhost (TMG server ) is allowed to access internet.
-services that are not necessary to be enabled such as print spooling, alert ...etc
-Checking for approvals for each rule created.
-security features such flood mitigation , IDS, ...etc.
-Logging is enabled.
-The reporting is healthy.
-The server is healthy : AV is installed, Local Admin PWD is complex ...etc.
* as a bottom line for auditors : if you have IT manager's approval for any exception even if allow any <->any , they will not write it down as a finding.
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