Users accessing WSS services via WSS agents
All users appear to be working fine and malware detection, policy execution returns expected status
A group of users that have recently rolled out the WSS agent however keep getting blocked and the custom error page rendered would indicate that
- every blocked URL is 'uncategorized' and
- every target is an IP address and not a domain name
WSS Admin has force deny rule enabled when match detected
They do have a valid DNS server and all blocked URLs can be successfully via nslookup.
A negate policy rule triggered all requests for the group of users to be blocked at the TCP layer before the HTTPS proxy can validate the request.
The TCP layer check failed based on the destination IP address not being categorised (which is often the case)
Force_deny rule implemented when matching rule found
Took existing single policy with negate logic and split it into two seperate policies.
The original policy checked to see if 'source' user was a member of group X and was NOT accessing any of the defined categories in a category list. This was turned into two rules:
- rule 1: if 'source' user was a member of group X and was accessing any of the defined categories in a category list user was entitled to access, ALLOW and
- rule 2: if 'source' user was a member of group X, force deny
We could not reproduce this in a test environment.
HTTP logs showed that all blocked users were accessing IP addresses at the time at TCP level, even though it should have gone up to HTTPS level
1234 2021-09-30 15:40:50 "DP2-GIEDU1_proxysg2" 12 188.8.131.52 BCOM\ncash "Domain Users, BCOM-Sitel-Webfiltering-Users" Global_Cloud_Proxy_Denied DENIED "Uncategorized" - 0 TCP_ACCELERATED TUNNEL - tcp 184.108.40.206 443 / - - - 192.168.2.85 0 0 - - - - 0 "client" client_connector "none" "none" 220.127.116.11 "United States" - - - - - none - - - - none - - ICAP_NOT_SCANNED - ICAP_NOT_SCANNED - - "None" - "Ireland" 5 - wss-agent architecture=x86_64%20name=Windows%2010%20Enterprise%20version=10.0.18363 18.104.22.16839 02bfd900-62c1-4622-b81c-4858e26a3287 ENLLH5CG1182SW9 - - - - - - - - - - 944fd17988c9a4c4-000000004a9e0676-000000006155da82
Policy trace showed force deny for TUNNELED (TCP) requests:
connection: service.name=HTTPS client.address=22.214.171.124 (NAT address=10.242.0.8) (effective address=126.96.36.199) proxy.port=443 source.port=15750 dest.port=443
time: 2021-09-30 16:16:46 UTC
RDNS lookup was restricted
user: name="BCOM\ncash" realm=cloud_realm group-bitset=00000001000000100001100000011 goi-version=145
user: name="BCOM\ncash" realm=cloud_realm
authentication start 1 elapsed 0 ms
authorization start 1 elapsed 0 ms
authentication status='none' authorization status='none'
te_user address='F373A2220' te_session address='F373A20A0'
user: authenticated=true authorized=true relative username='NCASH'
EXCEPTION(Global_Cloud_Proxy_Denied): Either 'force_deny' or 'force_exception' was matched in policy
url.category: [email protected];[email protected] Coat
total categorization time: 0
static categorization time: 0
outbound source IP: 188.8.131.52