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العربيةHijack instance role via Instance Connect
Can push an SSH key via Instance Connect and steal an instance's role.
Grants escalation only in combination. All of these are needed together:
ec2-instance-connect:SendSSHPublicKeyec2:DescribeInstancesec2-instance-connect:SendSSHPublicKey can push an SSH key via Instance Connect and steal an instance's role, but only when it is held together with ec2:DescribeInstances. Held together they reach administrator access.
Why it is dangerous
A principal can call ec2-instance-connect:SendSSHPublicKey to inject an ephemeral SSH key onto a running instance that already carries the instance-profile role, then SSH in over the network and read the instance's live credentials from IMDS. Because the instance is already bound to the box, a shell on it is enough to steal the role, no iam:PassRole needed. Unlike SSM this requires a reachable SSH port (22) on the instance, so it only works where the network path exists; if the instance is privileged this is full privilege escalation against an instance that was already trusted.
In MITRE ATT&CK terms this maps to T1578, Modify Cloud Compute Infrastructure, under the privilege escalation tactic. AWS records it in CloudTrail as SendSSHPublicKey, DescribeInstances. The call shows up in CloudTrail but blends into normal administration, so it needs a rule to stand out.
Detection
SendSSHPublicKeyDescribeInstancesPrerequisites
An existing running instance carrying an instance profile and reachable on its SSH port (22) from the attacker's position; ec2-instance-connect:SendSSHPublicKey permission. ec2:DescribeInstances enumerates targets and is checked against a wildcard. Instance Connect, unlike SSM, does NOT bypass the network path or security groups.
MITRE ATT&CK
T1578 · Modify Cloud Compute InfrastructureTactic
Privilege Escalation
A control that would remove it: Restrict ec2-instance-connect:SendSSHPublicKey to break-glass principals; close inbound port 22 and prefer SSM Session Manager.
Whether to apply it depends on how the permission is used in your environment, so it is a business decision rather than an automatic fix. The same permission can be load-bearing in one account and pure risk in another.
Pathbreak confirms whether this path resolves in your account, ranks it against the others by how much it opens up, and uses your threat model and business context to show which paths are worth cutting.
Questions
What does ec2-instance-connect:SendSSHPublicKey allow?
Can push an SSH key via Instance Connect and steal an instance's role.
What else is needed for ec2-instance-connect:SendSSHPublicKey to be dangerous?
It becomes an escalation only when held together with ec2:DescribeInstances. On its own it is not enough, which is what makes the combination easy to miss.
How is hijack instance role via Instance Connect detected?
Watch for SendSSHPublicKey, DescribeInstances in CloudTrail. The call shows up in CloudTrail but blends into normal administration, so it needs a rule to stand out.
How do you break this path?
A control that would remove it is: Restrict ec2-instance-connect:SendSSHPublicKey to break-glass principals; close inbound port 22 and prefer SSM Session Manager. Whether to apply it depends on how the permission is used in your account, so it is a business decision rather than an automatic fix.
Which MITRE ATT&CK technique is this?
T1578, Modify Cloud Compute Infrastructure, under the privilege escalation tactic.
Related paths
References
Find this in your own account
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