LOG_CVE_2021_27065_Exchange_Forensic_Artefacts_Mar21_2

YARA detection rule by Florian Roth (Nextron Systems) · NOASSERTION

Detects suspicious log entries that indicate requests as described in reports on HAFNIUM activity

rule LOG_CVE_2021_27065_Exchange_Forensic_Artefacts_Mar21_2 : LOG {
   meta:
      description = "Detects suspicious log entries that indicate requests as described in reports on HAFNIUM activity"
      author = "Florian Roth (Nextron Systems)"
      reference = "https://www.praetorian.com/blog/reproducing-proxylogon-exploit/"
      date = "2021-03-10"
      score = 65
      id = "37a26def-b360-518e-a4ab-9604a5b39afd"
   strings:
      $sr1 = /GET \/rpc\/ &CorrelationID=<empty>;&RequestId=[^\n]{40,600} (200|301|302)/
   condition:
      $sr1
}

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

723a0863-3f9b-4fd5-83bd-3bb2bd36f7ab

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

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