Suspicious awk Character Generation Piped to Shell on VMware ESXi (via process_creation)
- Product
- linux
- Category
- process_creation
- Author
- HuntRule
- Published
- 2026-05-03
- Updated
- 2026-08-28
ATT&CK techniques
Execution → Defense EvasionRecon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule detects awk being used to assemble command strings from numeric character codes on VMware ESXi. Actors abuse awk BEGIN blocks with printf and percent-c formatting to build obfuscated commands that are then piped into a shell. This construct rarely appears in legitimate ESXi administration.
Reporting behind it
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
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