BRUSHFIRE has the ability to exfiltrate data on-demand through executing commands obtained via monitoring for specially crafted packets and sending output back in an embedded SSL response.4
tool
BRUSHFIRE S9011
- Type
- malware
- Platforms
- Linux, Network Devices
- Created
- 13 April 2026
- Last modified
- 23 April 2026
BRUSHFIRE is a passive backdoor written in C that executes in-memory within an existing process. First reported in March 2025, BRUSHFIRE has been observed in activity attributed to People's Republic of China (PRC) state-affiliated threat actors, including UNC5221 and SYLVANITE.[1][2][3]
4
TechniquesBottom 17%
4
Tactics32nd pct
0
Threat groupsNone recorded
0
CampaignsNone recorded
Enterprise ATT&CK only. Any Mobile or ICS rows on the same ATT&CK page are not carried.
MITRE reference S9011
Standing S9011
Reach is how much of ATT&CK this tool 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
Techniques4Bottom 17%
17th percentile · 83% 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 groups061% 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 / technique2.5medBottom 2%
2nd percentile · 98% of 825 ATT&CK software entries have more detection rules per technique.
Tests / technique2.5med
Detection coverage S9011
25 distinct rules cover the 4 techniques recorded for this tool. 21 Sigma · 4 Splunk.
2 covered by at least one rule2 with no coverage25 distinct rules in total
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