build_downer can extract malware from a downloaded JPEG.2
tool
build_downer S0471
- Type
- malware
- Platform
- Windows
- Created
- 10 June 2020
- Last modified
- 25 April 2025
build_downer is a downloader that has been used by BRONZE BUTLER since at least 2019.[1]
8
Techniques38th pct
6
Tactics53rd pct
1
Threat groupunranked
0
CampaignsNone recorded
Enterprise ATT&CK only. Any Mobile or ICS rows on the same ATT&CK page are not carried.
MITRE reference S0471
build_downer has added itself to the Registry Run key as "NVIDIA" to appear legitimate.3
build_downer has the ability to download files from C2 to the infected host.4
build_downer has the ability to use the WinExec API to execute malware on a compromised host.5
build_downer has the ability to determine the local time to ensure malware installation only happens during the hours that the infected system is active.6
build_downer has the ability to detect if the infected host is running an anti-virus process.7
Standing S0471
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
Techniques838th pct
38th percentile · 62% of 825 ATT&CK software entries have more Enterprise techniques.
Tactics653rd pct
53rd percentile · 53% of 825 ATT&CK software entries have this many tactics spanned or fewer.
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 / technique7medBottom 9%
9th percentile · 91% of 825 ATT&CK software entries have more detection rules per technique.
Tests / technique5.5med
Detection coverage S0471
211 distinct rules cover the 8 techniques recorded for this tool. 161 Sigma · 50 Splunk.
7 covered by at least one rule1 with no coverage211 distinct rules in total
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