defection.io

malware

WellMail S0515

Type: malware
Platform: Windows
Created: 29 September 2020
Last modified: 25 April 2025

WellMail is a lightweight malware written in Golang used by APT29, similar in design and structure to WellMess.[1][2]

Techniques44th pct

Tactics32nd pct

Threat groupunranked

CampaignsNone recorded

Enterprise ATT&CK only. Any Mobile or ICS rows on the same ATT&CK page are not carried.

defection.io

malware

WellMail S0515

Type: malware
Platform: Windows
Created: 29 September 2020
Last modified: 25 April 2025

WellMail is a lightweight malware written in Golang used by APT29, similar in design and structure to WellMess.[1][2]

Techniques44th pct

Tactics32nd pct

Threat groupunranked

CampaignsNone recorded

Enterprise ATT&CK only. Any Mobile or ICS rows on the same ATT&CK page are not carried.

WellMail MITRE reference S0515

Data from Local System T1005 ↗

WellMail can exfiltrate files from the victim machine.3

Collection22 detection rules

System Network Configuration Discovery T1016 ↗

WellMail can identify the IP address of the victim system.4

Discovery25 detection rules

System Owner/User Discovery T1033 ↗

WellMail can identify the current username on the victim system.5

Discovery47 detection rules

Non-Application Layer Protocol T1095 ↗

WellMail can use TCP for C2 communications.6

Command and Control4 detection rules

Ingress Tool Transfer T1105 ↗

WellMail can receive data and executable scripts from C2.7

Command and Control131 detection rules

Deobfuscate/Decode Files or Information T1140 ↗

WellMail can decompress scripts received from C2.8

Stealth20 detection rules

Standing S0515

Reach is how much of ATT&CK this malware touches. Coverage is how well defended each thing it does is, as a median per technique rather than a total — a total would just restate the reach. Each figure is ranked against all 825 ATT&CK software entries only where that population actually spreads. Where most of the population shares one value, a percentile would rank the tie instead of the entity, so the raw value is shown and no rank is claimed.

Reach

Techniques944th pct

44th percentile · 56% of 825 ATT&CK software entries have more Enterprise techniques.

Tactics432nd pct

32nd percentile · 68% of 825 ATT&CK software entries have more tactics spanned.

Threat group161% tie · 22 values

61% of the population shares a single value across only 22 distinct values, so a percentile here would rank the tie, not the entity.

Campaigns085% tie · 8 values

85% of the population shares a single value across only 8 distinct values, so a percentile here would rank the tie, not the entity.

Coverage

Rules / technique20med47th pct

47th percentile · 53% of 825 ATT&CK software entries have more detection rules per technique.

Tests / technique5med42nd pct

42nd percentile · 58% of 825 ATT&CK software entries have more atomic tests per technique.

Data comps / technique4med54% tie · 11 values

54% of the population shares a single value across only 11 distinct values, so a percentile here would rank the tie, not the entity.

Mitigations / technique1med57th pct

57th percentile · 57% of 825 ATT&CK software entries have this many mitigations per technique or fewer.

5 of 8 axes carry an honest rank on this page. Coverage medians are taken across this malware’s 9 Enterprise techniques.

Range

Technique Campaign use over its cumulative rule count.

Campaigns · 0Sigma rules (cumulative) · 175Splunk ESCU (cumulative) · 87