S0515: WellMail
Security context for executives and security teams
S0515: WellMail describes [WellMail](https://attack.mitre.org/software/S0515) is a lightweight malware written in Golang used by [APT29](https://attack.mitre.org/groups/G0016), similar in design and structure to [WellMess](https://attack.mitre.org/software/S0514).(Citation: CISA WellMail July 2020)(Citation: NCSC APT29 July 2020)
Executive priority
S0515: WellMail 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 S0515: WellMail by reviewing the official ATT&CK relationships, mapped tactics (the mapped ATT&CK tactic context), supported platforms (Windows), 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 S0515: WellMail 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.
WellMail
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 | T1105 | Ingress Tool Transfer | |
| Enterprise | T1571 | Non-Standard Port | |
| Enterprise | T1560 | Archive Collected Data | |
| Enterprise | T1095 | Non-Application Layer Protocol | |
| Enterprise | T1033 | System Owner/User Discovery | |
| Enterprise | T1016 | System Network Configuration Discovery | |
| Enterprise | T1140 | Deobfuscate/Decode Files or Information | |
| Enterprise | T1573.002 | Asymmetric CryptographySub-technique | |
| Enterprise | T1005 | Data from Local System |
Groups, software, and campaigns
G0016: APT29
APT29 is threat group that has been attributed to Russia's Foreign Intelligence Service (SVR).[1][2] They have operated since at least 2008, often targeting government networks in Europe and NATO member countries, research institutes, and think tanks. APT29 reportedly compromised the Democratic National Committee starting in the summer of 2015.[3][4][5][6]
In April 2021, the US and UK governments attributed the SolarWinds Compromise to the SVR; public statements included citations to APT29, Cozy Bear, and The Dukes.[7][8] Industry reporting also referred to the actors involved in this campaign as UNC2452, NOBELIUM, StellarParticle, Dark Halo, and SolarStorm.[9][10][11][12][13][14]
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(3)
| Release | Bundle imported | Object version | Modified | Status | Raw hash |
|---|---|---|---|---|---|
| 20.0 | 1.0 | Current bundle | ec437100d55a… | ||
| 19.2 | 1.0 | Older bundle | ec437100d55a… | ||
| 19.1 | 1.0 | Older bundle | ec437100d55a… |
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]CISA WellMail July 2020
CISA. (2020, July 16). MAR-10296782-3.v1 – WELLMAIL. Retrieved September 29, 2020.
Open source URL - [2]NCSC APT29 July 2020
National Cyber Security Centre. (2020, July 16). Advisory: APT29 targets COVID-19 vaccine development. Retrieved September 29, 2020.
Open source URL - [3]mitre-attackS0515Open source URL
Source: MITRE ATT&CK®. © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation. Glexia is not affiliated with or endorsed by MITRE.