PROXY-01: vsock-proxy egress allowlist is least-privilege¶
| Property | Value |
|---|---|
| Severity | high |
| Platform | AWS Nitro Enclaves |
| Lifecycle stage | runtime |
| Mode | Active: runs fixed read-only commands on the host. Skipped with --read-only. |
What it checks¶
It passes when:
- vsock-proxy allowlist scopes egress to … specific endpoint(s); no unbounded entries.
Example failures:
- … vsock-proxy allowlist entry(ies) permit unbounded egress: …. The enclave can exfiltrate to arbitrary hosts.
- 1 vsock-proxy allowlist entry(ies) permit unbounded egress: 0.0.0.0:443 (any-address). The enclave can exfiltrate to arbitrary hosts.
How to fix¶
- Restrict /etc/nitro_enclaves/vsock-proxy.yaml to the specific {address, port} endpoints the enclave must reach (e.g. the regional KMS endpoint on 443); remove any-address (0.0.0.0/*) and any-port entries.
After the fix, scan again: the check should report PASS.
When it is not assessed¶
SKIP:
- No instance ID specified; skipping check.
ERROR:
- Could not read the vsock-proxy allowlist: …
Scan inputs¶
The untrust scan options this check reads:
| Option | Description |
|---|---|
--instance-id |
EC2 instance ID running the Nitro Enclave. |
--region |
AWS region. |
Permissions¶
The cloud API calls this check makes, read from the scanner's source:
| Cloud | API call | Permission | Access |
|---|---|---|---|
| AWS | ssm.get_command_invocation |
ssm:GetCommandInvocation |
read |
| AWS | ssm.send_command |
ssm:SendCommand |
run command |
Every AWS scan also calls sts:GetCallerIdentity. See Required permissions for a complete policy.
Evidence recorded¶
Keys in the finding's evidence: broad_entries, entry_count, passed
Generated from untrust 1.3.0 (commit 7ef462d9a0c3).