tool
Kobalos S0641
- Type
- malware
- Platform
- Linux
- Created
- 24 August 2021
- Last modified
- 25 April 2025
Kobalos is a multi-platform backdoor that can be used against Linux, FreeBSD, and Solaris. Kobalos has been deployed against high profile targets, including high-performance computers, academic servers, an endpoint security vendor, and a large internet service provider; it has been found in Europe, North America, and Asia. Kobalos was first identified in late 2019.[1][2]
Enterprise ATT&CK only. Any Mobile or ICS rows on the same ATT&CK page are not carried.
MITRE reference S0641
Kobalos encrypts all strings using RC4 and bundles all functionality into a single function call.4
Kobalos can exfiltrate credentials over the network via UDP.5
Kobalos has used a compromised SSH client to capture the hostname, port, username and password used to establish an SSH connection from the compromised host.67
Kobalos can spawn a new pseudo-terminal and execute arbitrary commands at the command prompt.8
Kobalos can remove all command history on compromised hosts.9
Standing S0641
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
66th percentile · 66% of 825 ATT&CK software entries have this many Enterprise techniques or fewer.
80th percentile · 80% of 825 ATT&CK software entries have this many tactics spanned or fewer.
61% of the population shares a single value across only 22 distinct values, so a percentile here would rank the tie, not the entity.
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
15th percentile · 85% of 825 ATT&CK software entries have more detection rules per technique.
Detection coverage S0641
297 distinct rules cover the 15 techniques recorded for this tool. The 309 technique-to-rule mappings resolve to 297 distinct rules, because one rule can cover several techniques. 228 Sigma · 69 Splunk.
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