S1121: LITTLELAMB.WOOLTEA
LITTLELAMB.WOOLTEA is a backdoor that was used by UNC5325 during Cutting Edge to deploy malware on targeted Ivanti Connect Secure VPNs and to establish persistence across system upgrades and patches.[1]
Security context for executives and security teams
S1121: LITTLELAMB.WOOLTEA describes [LITTLELAMB.WOOLTEA](https://attack.mitre.org/software/S1121) is a backdoor that was used by UNC5325 during [Cutting Edge](https://attack.mitre.org/campaigns/C0029) to deploy malware on targeted Ivanti Connect Secure VPNs and to establish persistence across system upgrades and patches.(Citation: Mandiant Cutting Edge Part 3 February 2024)
Executive priority
S1121: LITTLELAMB.WOOLTEA 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 S1121: LITTLELAMB.WOOLTEA 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 S1121: LITTLELAMB.WOOLTEA 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.
LITTLELAMB.WOOLTEA
LITTLELAMB.WOOLTEA is a backdoor that was used by UNC5325 during Cutting Edge to deploy malware on targeted Ivanti Connect Secure VPNs and to establish persistence across system upgrades and patches.[1]
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 | LITTLELAMB.WOOLTEA can function as a stand-alone backdoor communicating over the `/tmp/clientsDownload.sock` socket.[1] |
| Enterprise | T1090 | Proxy | LITTLELAMB.WOOLTEA has the ability to function as a SOCKS proxy.[1] |
| Enterprise | T1573.002 | Asymmetric CryptographySub-technique | LITTLELAMB.WOOLTEA can communicate over SSL using the private key from the Ivanti Connect Secure web server.[1] |
| Enterprise | T1554 | Compromise Host Software Binary | LITTLELAMB.WOOLTEA can append malicious components to the `tmp/tmpmnt/bin/samba_upgrade.tar` archive inside the factory reset partition in attempt to persist post reset.[1] |
| Enterprise | T1543 | Create or Modify System Process | LITTLELAMB.WOOLTEA can initialize itself as a daemon to run persistently in the background.[1] |
| Enterprise | T1083 | File and Directory Discovery | LITTLELAMB.WOOLTEA can monitor for system upgrade events by checking for the presence of `/tmp/data/root/dev`.[1] |
| Enterprise | T1082 | System Information Discovery | LITTLELAMB.WOOLTEA can check the type of Ivanti VPN device it is running on by executing `first_run()` to identify the first four bytes of the motherboard serial number.[1] |
Groups, software, and campaigns
C0029: Cutting Edge
Cutting Edge was a campaign conducted by suspected China-nexus espionage actors, variously identified as UNC5221/UTA0178 and UNC5325, that began as early as December 2023 with the exploitation of zero-day vulnerabilities in Ivanti Connect Secure (previously Pulse Secure) VPN appliances. Cutting Edge targeted the U.S. defense industrial base and multiple sectors globally including telecommunications, financial, aerospace, and technology. Cutting Edge featured the use of defense evasion and living-off-the-land (LoTL) techniques along with the deployment of web shells and other custom malware.[1][2][3][4][5]
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 | 1.1 | Current bundle | 04c4d8f10ad7… | ||
| 19.1 | 1.1 | Older bundle | 04c4d8f10ad7… |
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]Mandiant Cutting Edge Part 3 February 2024
Lin, M. et al. (2024, February 27). Cutting Edge, Part 3: Investigating Ivanti Connect Secure VPN Exploitation and Persistence Attempts. Retrieved March 1, 2024.
Open source URL - [2]mitre-attackS1121Open source URL
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