ET INFO Observed External IP Lookup Domain (ipleak .net) in TLS SNI

Query · suricata

flow:established,to_server;
tls.sni;
content:"ipleak.net"; endswith; fast_pattern;

Atomic IOCs

The whole rule is one thing the adversary controls: a domain, an IP, a file hash. It stops working the moment that value rotates. Collapses the pyramid's bottom three rungs, which structure cannot reliably tell apart. Hidden by default: useful for asking 'has anyone seen this?', misleading as a measure of coverage.
Network & Host Artifacts

A URI shape, a user-agent, a registry path. These are the marks left behind when the adversary's tooling runs. Survives the rotation of any single domain or hash; breaks when the tool is reconfigured.
Tools

Identifies the software rather than the traces of it. Most YARA rules sit here, as do Suricata rules keyed on a hardcoded user-agent. Costs the adversary a rebuild or a new tool.
TTPs

Describes the action rather than anything the adversary owns or used: a process spawning another, a sequence of events, a join across other detections. Survives a tool swap, and the rung worth comparing across sources.
Pending classification

A classifier read the rule and structure alone did not settle it. Every rule in the index has been examined and none is skipped, so these are held for a later pass rather than guessed at. A wrong rung is worse than none. Concentrated in the formats whose rules say least about what they key on.

TA0043 T1590