Encrypt Session Manager sessions by using the service’s encryption options with customer-managed key material where required, and enable session logging to a central log destination. Capture both session metadata and the session transcript so activity can be reviewed later. Restrict who can start sessions and who can read the logs.
What encrypting and logging a Session Manager session actually means
For aws systems manager Session Manager, encryption and logging solve two different problems. Encryption protects the session channel and any transcript material handled through the service, while logging gives you a reviewable record of who connected, when they connected, and what was done. In practice, both are needed because a private session without a transcript leaves too little evidence, and logs without strong access control can become a second sensitive target.
AWS Security Guide is the right starting point when you want the broader AWS control picture around CloudTrail, KMS, IAM Identity Center, and logging design. Session Manager fits that wider pattern: the service should be treated as part of your AWS access architecture, not as an isolated shell feature.
How to design the encryption and transcript path
The practical design choice is to separate transport/session protection from transcript retention. Use the service encryption options with customer-managed key material where required, then send the transcript to a central destination that your security team can retain, search, and protect independently. That keeps the audit record under your own control instead of leaving it scattered across instance disks or operator laptops.
For the key path, the important judgement is whether your policy requires customer control over the encryption key lifecycle, rotation, and access policy. If it does, prefer a customer-managed KMS key rather than relying on a default service-managed posture. That matters most where sessions may carry administrative activity, production troubleshooting, or access into regulated environments.
Secrets Management Buyer’s Guide is useful here because the same operational question appears with session encryption: who controls the secret material, how tightly is access limited, and how easy is it to rotate or replace when policy changes. Even though Session Manager is not a secrets manager, the governance logic is similar.
What to log, and what the logs must let you prove
Logging Session Manager well means capturing both session metadata and the transcript. Metadata tells you who started the session, against which target, under what time window, and through which path. The transcript tells you what the operator actually did after access was granted. If you only keep one of those, you will usually have either weak accountability or weak forensic value.
Centralising the logs is the other half of the design. A central log destination makes retention, access review, detection, and legal hold much easier than relying on local or ad hoc storage. It also makes it possible to correlate the session with surrounding control-plane events, which is where many investigations start.
Cloud Credential Compromise Playbook maps closely to this logging model because session records are often what you need after suspicious access has already occurred. The record is most valuable when it supports containment decisions, session revocation, and reconstruction of operator activity.
Who should be allowed to start sessions or read the logs
Session Manager is a privilege boundary, so access must be restricted on both sides. The people who can start sessions should be narrower than the people who can read logs, and the people who can read transcripts should usually be narrower still. That separation prevents the common failure mode where operational staff can both enter a host and erase the evidence trail around that access.
Good practice is to treat session start permissions as an administrative privilege and log access as an audit privilege, then review both sets independently. If your workflow needs broad operator access, use explicit approval or break-glass handling instead of open-ended standing permission. The tighter the target system, the more important it is to keep session initiation and transcript visibility separated.
Risk and Threat Considerations
Session Manager reduces exposure compared with unmanaged SSH or RDP access, but it also concentrates privileged access into a small number of control points. If the encryption key policy is weak, the transcript destination is poorly protected, or session start rights are too broad, attackers can abuse the same trusted path that administrators use for legitimate access.
Failure mechanism: An attacker who gains high-privilege access, or an insider with excessive rights, can create sessions, hide activity in an underprotected transcript store, or use missing logs to reduce detection and investigation quality.
Impact: You can lose both containment and attribution. That means harder incident response, weaker evidence for post-incident review, and a greater chance that privileged actions on production systems go unchallenged.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST SP 800-53 Rev 5 provides the primary governance reference for this topic.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | IA-2 — Identification and Authentication (Organizational Users) | Session start access depends on authenticating admins and operators. |
| AU-2 — Audit Events | Session metadata and transcripts are audit evidence for privileged activity. | |
| AC-6 — Least Privilege | Session initiation and log reading should be tightly separated by role. | |
| Recommendation — Enforce strong authentication for users allowed to start interactive sessions. Define and capture the Session Manager events and transcript records you must retain. Restrict session start and log-read permissions to the minimum set of roles. | ||
Practitioner Guidance
What to verify: Confirm that your logging path captures both metadata and transcripts, that the transcript destination is centrally managed, and that only a limited role set can read it. If any of those three is missing, treat the deployment as incomplete even if the session itself is encrypted.
Decision rule: If the session can reach production or sensitive data, prioritise customer-controlled encryption and strict log access before convenience features or broad operator access. If you need to relax either control, document the exception and put a review date on it.
Practitioner takeaway: Session Manager is secure enough only when the session, the key material, and the audit trail are governed as one access-control problem. Encrypting without durable logging, or logging without tight access control, leaves a privileged path that is easier to use than it is to defend.
Related resources from NHI Mgmt Group
- How should security teams reduce the risk of lateral movement when AWS Systems Manager is enabled in hybrid environments?
- Why does AWS Systems Manager increase the impact of compromised credentials in hybrid cloud networks?
- What are the signs that AWS Systems Manager is being misused for persistence or credential theft?
- What happens when attackers use AWS Systems Manager without tight access controls?