S1204: cd00r
cd00r is an open-source backdoor for UNIX and UNIX-variant operating systems that was orginally released in 2000. cd00r source code is primarily based on a packet-capturing program as it utilizes a sniffer to listen for specific sequences of network traffic or "secret knock" before executing the attacker's code.[1][2]
Security context for executives and security teams
S1204: cd00r describes [cd00r](https://attack.mitre.org/software/S1204) is an open-source backdoor for UNIX and UNIX-variant operating systems that was orginally released in 2000. [cd00r](https://attack.mitre.org/software/S1204) source code is primarily based on a packet-capturing program as it utilizes a sniffer to listen for specific sequences of network traffic or "secret knock" before executing the attacker's code.(Citation: Hartrell cd00r 2002)(Citation: Lumen J-Magic JAN 2025)
Executive priority
S1204: cd00r is an official MITRE ATT&CK software. Glexia treats it as defensive behavior context for prioritizing monitoring, control validation, and response planning without using the object by itself as an attribution claim.
Technical view
Security teams should validate S1204: cd00r by reviewing the official ATT&CK relationships, mapped tactics (the mapped ATT&CK tactic context), supported platforms (Network Devices), and available local telemetry before making detection or mitigation decisions.
Likely telemetry
- Official ATT&CK relationships and object metadata
- Network, endpoint, and security-tool telemetry
Detection direction
- Validate whether S1204: cd00r appears in your detection coverage and tabletop scenarios.
- Use the object to align executive risk language with SOC, incident response, and detection engineering work.
- Do not treat ATT&CK relationship context as attribution without corroborating evidence.
Mitigation priorities
- Map the object to existing controls and identify missing telemetry or response ownership.
- Prioritize mitigations that reduce exposure on the listed platforms and tactics.
- Review adjacent ATT&CK relationships before changing policy, detections, or reporting language.
Additional notes and limits
Baseline Glexia take generated from the official MITRE ATT&CK STIX object, source hash, tactics, platforms, and detection fields. It is safe to replace with a richer model-generated take for the same source hash later.
This baseline take is source-grounded and schema-validated, but it does not include environment-specific telemetry, incident evidence, or threat-intelligence corroboration.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
cd00r
cd00r is an open-source backdoor for UNIX and UNIX-variant operating systems that was orginally released in 2000. cd00r source code is primarily based on a packet-capturing program as it utilizes a sniffer to listen for specific sequences of network traffic or "secret knock" before executing the attacker's code.[1][2]
How security teams should use this page
Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.
Techniques used
This mirrors the MITRE pattern of making group, software, campaign, and technique relationships scannable. Relationship notes come from mirrored ATT&CK relationship text when available.
| Domain | ID | Name | Relationship / procedure |
|---|---|---|---|
| Enterprise | T1095 | Non-Application Layer Protocol | |
| Enterprise | T1016 | System Network Configuration Discovery | |
| Enterprise | T1040 | Network Sniffing | |
| Enterprise | T1205.001 | Port KnockingSub-technique |
All related ATT&CK context
Object version and sync metadata
The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates.
Imported snapshots across ATT&CK releases(2)
| Release | Bundle imported | Object version | Modified | Status | Raw hash |
|---|---|---|---|---|---|
| 19.2 | 1.0 | Current bundle | c59934d8e542… | ||
| 19.1 | 1.0 | Older bundle | c59934d8e542… |
Mirrored ATT&CK source object
The raw object is retained through the mirrored ATT&CK source bundle and object hash. The raw endpoint returns the exact object from the mirrored bundle when available.
External references and citations
MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.
- [1]Hartrell cd00r 2002
Hartrell, Greg. (2002, August). Get a handle on cd00r: The invisible backdoor. Retrieved October 13, 2018.
Open source URL - [2]Lumen J-Magic JAN 2025
Black Lotus Labs. (2025, January 23). The J-Magic Show: Magic Packets and Where to find them. Retrieved February 17, 2025.
Open source URL - [3]mitre-attackS1204Open source URL
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