Exploiting AWS IAM Eventual Consistency: The Persistence Risk Every Cloud Defender Must Understand

AWS Identity and Access Management (IAM) is often perceived as a strongly consistent and immediate-response system. However, like many globally distributed services, it actually operates on an eventual consistency model. While this design enables scalability across regions, it also introduces brief but dangerous windows that attackers can exploit to maintain persistence — even after defenders believe they have removed access.

Recent testing and analysis by OFFENSAI highlights how these delays can be weaponized to re-establish or retain access in the critical first seconds of an incident response.

The Consistency Gap: 3–4 Seconds of Vulnerability

AWS IAM updates — including access key deletion, policy changes, and role modifications — take approximately 3–4 seconds to propagate globally.
OFFENSAI validated this timing across regions such as us-east-1 and eu-central-1.

During this propagation window:

Deleted access keys remain usable for API calls
Key listings may return an empty array despite the key still being active
Attackers can sometimes generate new access keys before invalidation completes
Policy updates may not enforce immediately
Deny-all policies may be visible to the attacker before fully applied

This creates a micro-window that advanced adversaries can leverage to maintain persistence.

Case Study: Access Keys Still Work After Deletion

In a simulated attack scenario:

A defender deletes a compromised access key using:
aws iam delete-access-key --access-key-id AKIA... --user-name bob
Within the consistency lag window, the attacker is still able to:
- Make valid API calls using the “deleted” key
- Detect the deletion through IAM APIs that return inconsistent results
- Attempt creation of new access keys before propagation completes

CloudTrail logs show both actions accurately — deletion and post-deletion API calls — but the system’s replication delay is enough to allow persistence.

This behavior extends beyond access keys to:

Policy attachments
Role deletions
User login profile modifications

This amplification makes incident response more challenging and time-sensitive.

Why Traditional Incident Response Playbooks Fail

Many defenders rely on emergency measures like applying AWSDenyAll to stop malicious activity during an active incident.

However, OFFENSAI’s tests revealed:

Deny-all policies experience the same propagation delay
Attackers can detect changes almost instantly
Polling commands such as ListAccessKeys reveal inconsistencies
Attackers may detach newly applied policies before enforcement fully propagates

Additionally, AWS’s own Credential Cleanup Procedure (from re:Post) recommends waiting for propagation — a process attackers can race against.

Post-Disclosure Observations and Partial Fixes

After OFFENSAI’s disclosure:

AWS implemented a fix preventing creation of new keys immediately after key deletion
AWS acknowledged the findings in April 2025
Documentation updates clarified IAM consistency expectations
AWS did not classify the issue as a vulnerability, describing it instead as a property of distributed system design

However, testing on December 5, 2025 shows remaining gaps:

Attackers can still monitor changes during propagation delays
Existing assumable roles (especially with AdministratorAccess) remain a critical risk
External accounts may exploit stale permissions before propagation completes

Recommended Defensive Strategies

To mitigate persistence risks created by IAM’s eventual consistency:

1. Use Service Control Policies (SCPs) at the AWS Organizations level

SCPs apply before account-level IAM policies, giving defenders an authoritative way to lock attackers out.

Attackers cannot override or modify SCPs from within a compromised account.

2. Prefer IAM Roles + Temporary STS Tokens

Long-term access keys are the primary target and easiest to exploit during propagation windows.

Short-lived STS credentials reduce exposure dramatically.

3. Update Detection Logic

SIEM and SOAR playbooks should account for:

Stale key usage post-deletion
Policy updates followed by suspicious API calls
Access attempts from deleted principals during propagation lag

4. Enhance Incident Response Playbooks

Defenders must assume a 3–4 second race condition exists and act accordingly:

Combine multiple layered actions (policy detachments, SCPs, role quarantine)
Monitor CloudTrail for post-deletion API activity
Immediately revoke STS tokens when possible

5. Perform Post-Incident Thorough Cleanup

After IAM changes fully propagate, perform:

Key rotations
Role trust policy reviews
IAM permission audits
Deletion of unused roles or users

No Known In-The-Wild Exploits — But Don’t Be Complacent

As of December 2025, no active exploitation has been discovered in the wild.
However, the mechanics closely resemble real-world attacker behaviors:

Fast-reaction persistence
API polling for defender activity
Abuse of IAM role assumptions

Organizations adopting a proactive posture will be better prepared than those who rely solely on traditional key deletion practices.

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AWS IAM Eventual Consistency: The Overlooked Persistence Technique