Detect CVE-2026-46595: golang.org/x/crypto/ssh VerifiedPublicKeyCallback Authentication Bypass in IBM QRadar
Detects exploitation of CVE-2026-46595, a critical authentication bypass vulnerability (CVSS 10.0) in golang.org/x/crypto/ssh versions prior to 0.52.0. When VerifiedPublicKeyCallback is used, SSH server implementations fail to enforce permission checks, allowing attackers to authenticate without proper authorization. This is a regression/variant of CVE-2024-45337 and carries a public PoC.
MITRE ATT&CK
QRadar Detection Query
SELECT
DATEFORMAT(starttime, 'YYYY-MM-dd HH:mm:ss') AS event_time,
sourceip,
destinationip,
username,
QIDNAME(qid) AS event_name,
category,
logsourcename(logsourceid) AS log_source,
"eventcount",
UTF8(payload) AS raw_payload
FROM events
WHERE
LOGSOURCETYPENAME(devicetype) IN ('Linux OS', 'SolarWinds Orion', 'OpenSSH')
AND (
UTF8(payload) ILIKE '%Accepted publickey%'
OR UTF8(payload) ILIKE '%publickey authentication%'
OR UTF8(payload) ILIKE '%VerifiedPublicKeyCallback%'
OR UTF8(payload) ILIKE '%golang.org/x/crypto/ssh%'
)
AND category IN (5000, 5001, 5002, 5003)
AND username IS NOT NULL
AND username != ''
LAST 24 HOURS
ORDER BY starttime DESCQRadar AQL query to identify SSH authentication events potentially exploiting CVE-2026-46595 by searching for publickey authentication successes on Go SSH server implementations across Linux and SSH log sources.
Data Sources
Required Tables
False Positives & Tuning
- Routine SSH public key authentication by system administrators and developers
- Automated backup systems and monitoring agents authenticating via SSH keys
- Configuration management tools such as Ansible and Puppet using SSH key authentication
- Service accounts performing legitimate programmatic SSH operations
Other platforms for CVE-2026-46595
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 1CVE-2026-46595 PoC: VerifiedPublicKeyCallback Auth Bypass Simulation
Expected signal: SSH authentication log entry showing 'Accepted publickey for testuser' despite the key not being in the authorized_keys list or having required permissions. Process execution events showing 'id', 'hostname', and echo commands as child processes of the SSH daemon.
- Test 2Identify Vulnerable golang.org/x/crypto/ssh Deployments via Binary Inspection
Expected signal: Process execution events for 'go' binary with 'version -m' arguments, file access events on Go binaries in /usr/local/bin, /usr/bin, /opt, and /proc/*/exe paths.
- Test 3SSH Brute-Force Simulation Against Go SSH Server to Test Alerting
Expected signal: Multiple 'Invalid user' or 'Failed publickey' log entries from the lab host IP, followed by potential 'Accepted publickey' entries if testing against a vulnerable server. Network connection events on the SSH port from the test machine.
References (7)
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