Detect Check Point Security Gateway Improper Authentication (CVE-2026-50751) in Sumo Logic CSE
Detects exploitation of CVE-2026-50751, an improper authentication vulnerability (CWE-287) in Check Point Security Gateway affecting deprecated IKEv1 VPN protocol. This vulnerability is actively exploited in the wild (CISA KEV) and may allow unauthenticated attackers to bypass authentication controls on the VPN gateway. Detection focuses on anomalous IKEv1 negotiation patterns, authentication bypass indicators, and suspicious gateway access following failed or malformed IKE exchanges.
MITRE ATT&CK
- Tactic
- Initial Access Credential Access
Sumo Detection Query
_sourceCategory=firewall/checkpoint OR _sourceCategory=network/vpn
| where vendor = "Check Point" or _sourceName matches "*checkpoint*"
| where message matches "*IKEv1*" or message matches "*aggressive mode*" or message matches "*ikev1*"
or (message matches "*authentication*" and (message matches "*fail*" or message matches "*bypass*" or message matches "*unauthenticated*"))
| where _sourcePort = 500 or _sourcePort = 4500 or dest_port = 500 or dest_port = 4500
| timeslice 5m
| count by src_ip, _sourceHost, _timeslice
| where _count > 2
| sort by _count descSumo Logic query for identifying Check Point Security Gateway IKEv1 authentication anomalies consistent with CVE-2026-50751 exploitation, bucketed into 5-minute windows by source IP.
Data Sources
Required Tables
False Positives & Tuning
- Automated VPN tunnel re-establishment from branch offices still using IKEv1 profiles
- Load balancer health probes hitting the VPN gateway on UDP 500
- Penetration testers running IKEscan or similar tools against the gateway
Other platforms for CVE-2026-50751
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1IKEv1 Aggressive Mode Probe — Check Point Gateway
Expected signal: Check Point SmartLog IKE phase 1 event with protocol IKEv1, mode aggressive, from the test host IP. UDP/500 connection event in network logs.
- Test 2Repeated IKEv1 Auth Failure Simulation
Expected signal: 10 IKEv1 negotiation attempts with authentication failure events in SmartLog. Source IP flagged in Check Point IPS/firewall blade logs.
- Test 3IKEv1 vs IKEv2 Protocol Downgrade Attempt
Expected signal: StrongSwan IKEv1 initiation attempt visible in system logs; Check Point gateway logs showing inbound IKEv1 proposal from test host on UDP/500.
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Get the full detection package for CVE-2026-50751 including response playbook, investigation guide, and atomic red team tests.