Identifies an unexpected file being modified by dns.exe, the process responsible for Windows DNS Server services, which may indicate activity related to remote code execution or other forms of exploitation.
Rule type: eql
Risk score: 73
Runs every: 5m
Maximum alerts per execution: 100
- Threat Detection
- Initial Access
Rule license: Elastic License v2
## Triage and analysis ### Investigating Unusual File Write Detection alerts from this rule indicate potential unusual/abnormal file writes from the DNS Server service process (`dns.exe`) after exploitation from CVE-2020-1350 (SigRed) has occurred. Here are some possible avenues of investigation: - Post-exploitation, adversaries may write additional files or payloads to the system as additional discovery/exploitation/persistence mechanisms. - Any suspicious or abnormal files written from `dns.exe` should be reviewed and investigated with care. ## Config If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
file where process.name : "dns.exe" and event.type in ("creation", "deletion", "change") and not file.name : "dns.log"
Framework: MITRE ATT&CKTM