BeaverTail has added junk data or a dummy character prepended to a string to hamper decoding attempts.5
tool
BeaverTail S1246
- Type
- malware
- Platforms
- Linux, macOS, Windows
- Created
- 19 October 2025
- Last modified
- 24 October 2025
BeaverTail is a malware that has both a JavaScript and C++ variant. Active since 2022, BeaverTail is capable of stealing logins from browsers and serves as a downloader for second stage payloads. BeaverTail has previously been leveraged by North Korea-affiliated actors identified as DeceptiveDevelopment or Contagious Interview. BeaverTail has been delivered to victims through code repository sites and has been embedded within malicious attachments.[1][2][3][4]
23
TechniquesTop 15%
9
TacticsTop 11%
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 S1246
BeaverTail has exfiltrated data collected from local systems.6789
BeaverTail has obfuscated strings of code with Base64 encoding within the JavaScript version of the malware.101112 BeaverTail has also utilized the open-source tool JavaScript-Obfuscator to obfuscate strings and functions.1314
BeaverTail has masqueraded as MiroTalk installation packages: “MiroTalk.dmg” for macOS and “MiroTalk.msi” for Windows, and has included login GUIs with MiroTalk themes.15
BeaverTail has exfiltrated data collected from victim devices to C2 servers.161718
BeaverTail has executed malicious JavaScript code.1920212223 BeaverTail has also been compiled with the Qt framework to execute in both Windows and macOS.24
Standing S1246
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
Techniques23Top 15%
85th percentile · 85% of 825 ATT&CK software entries have this many Enterprise techniques or fewer.
Tactics9Top 11%
89th percentile · 89% 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 / technique13medBottom 25%
25th percentile · 75% of 825 ATT&CK software entries have more detection rules per technique.
Tests / technique3med
Detection coverage S1246
539 distinct rules cover the 23 techniques recorded for this tool. The 570 technique-to-rule mappings resolve to 539 distinct rules, because one rule can cover several techniques. 367 Sigma · 172 Splunk.
21 covered by at least one rule2 with no coverage539 distinct rules in total
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