Which logs show evidence of Pass the Key?

What logs point to Pass the Key activity?

The most useful evidence is in authentication and session logs, not in one isolated alert. Pass the Key often shows up as a successful logon using valid key material from an endpoint, host, or session that does not fit the account’s normal source, timing, or device profile. The key question is whether the authentication event is plausible for that identity.

Kerberos-focused logs are especially important because Pass the Key relies on trusted credentials being replayed or reused rather than guessed. Look for ticket activity that aligns with an unusual host, a different workstation pattern, or an account suddenly authenticating where it normally does not. Kerberos Security Guide is the most direct reference point for understanding how ticket abuse and related Kerberos detections fit together.

Host logon events matter because they show where the credentials were actually used. When a logon appears legitimate at the protocol layer but is followed by remote execution, service access, or movement from an unexpected endpoint, the combined trail often tells the story more clearly than any single event. That is why logs should be read as a chain: authentication, host access, then lateral movement.

Which correlations make the evidence convincing?

The strongest indicator is correlation across identity, host, and movement telemetry. One record may show a valid logon, but the surrounding logs can reveal that the session came from a device the user never normally uses, occurred at an odd time, or was immediately followed by access to systems that are not part of the account’s normal scope.

In practice, the best comparisons are against the account’s baseline behaviour. If the account usually authenticates from one subnet, one workstation set, or one business process window, then a new logon from a different origin deserves attention. This is where unusual endpoint use becomes meaningful, because Pass the Key is often about reusing existing trust on a machine that should not normally be able to act for that identity.

Remote service and movement logs also help distinguish ordinary admin work from abuse. If the same key material is used to access hosts that are operationally unrelated, the log trail may show a sequence consistent with lateral movement rather than routine administration. The value is not just in seeing a logon, but in seeing the downstream actions that make the logon suspicious.

For Windows environments, Lateral Movement Guide provides the practical context for interpreting those follow-on events, especially when remote services, admin shares, or stolen credentials are involved.

What should analysts look for before calling it Pass the Key?

First confirm that the event is not just an unusual but still legitimate admin workflow. Scheduled maintenance, jump hosts, shared service workflows, and delegated operations can all resemble abuse if you do not know the environment. The distinction usually comes from whether the source, device, and sequence of actions match an approved pattern.

Next verify whether the logon aligns with other signs of compromise. A single successful authentication is weaker evidence than a cluster of events that includes unusual ticket use, remote access to new systems, or a change in the account’s normal access pattern. The more the session looks like it borrowed trust from a different machine or context, the stronger the case.

Also check whether the relevant logs are complete enough to support the claim. If you only have one side of the story, such as domain authentication without endpoint detail, you may miss the origin of the activity or misread a benign administrative session as malicious use of key material.

Risk and Threat Considerations

Pass the Key is dangerous because it lets an attacker operate with valid authentication material instead of noisy brute force. That can produce logins that look acceptable in isolation, which makes correlation across Kerberos, host, and lateral movement logs essential for spotting abuse.

Failure mechanism: An attacker who obtains key material can replay or reuse it from a different endpoint, causing authentication to succeed even though the source device, timing, and downstream activity no longer match the account’s normal behaviour.

Impact: The result can be stealthy lateral movement, unauthorized host access, and delayed detection because the session inherits the trust of a valid identity rather than triggering an obvious password failure.

Practitioner Guidance

What to verify: Compare the source host, logon type, Kerberos activity, and subsequent remote actions against the account’s known baseline before escalating. A single successful logon is rarely enough on its own; the surrounding sequence is what makes the event actionable.

What practitioners underestimate: The best evidence often comes from mismatch, not from a signature. A valid authentication that originates from the wrong device and is followed by lateral movement is more informative than a simple “successful logon” alert.

Practitioner takeaway: Treat Pass the Key as a correlation problem. The goal is to prove that the authentication, source, and follow-on activity belong to the same normal operational pattern, and to investigate aggressively when they do not.

Related resources from NHI Mgmt Group

• How should security teams respond when authentication logs do not show enough detail to detect pass-the-ticket or forged Kerberos activity?
• Which logs show evidence of fast-flux DNS?
• Which logs show evidence of Modify Cloud Compute Infrastructure?
• Which logs show evidence of Create Cloud Instance?