SUSP_ScreenConnect_User_2024_No_Logon_Feb24

YARA detection rule by Florian Roth · NOASSERTION

Detects suspicious ScreenConnect user created in 2024 but without any login, which could be a sign of exploitation of the ConnectWise ScreenConnect (versions prior to 23.9.8) vulnerability that allows an Authentication Bypass

rule SUSP_ScreenConnect_User_2024_No_Logon_Feb24 {
   meta:
      description = "Detects suspicious ScreenConnect user created in 2024 but without any login, which could be a sign of exploitation of the ConnectWise ScreenConnect (versions prior to 23.9.8) vulnerability that allows an Authentication Bypass"
      author = "Florian Roth"
      reference = "https://github.com/watchtowrlabs/connectwise-screenconnect_auth-bypass-add-user-poc/blob/45e5b2f699a4d8f2d59ec3fc79a2e3c99db71882/watchtowr-vs-ConnectWise_2024-02-21.py#L53"
      date = "2024-02-23"
      score = 60
      id = "c0861f1c-08e2-565d-a468-2075c51b4004"
   strings:
      $a1 = "<Users xmlns:xsi="
      $a2 = "<CreationDate>"

      $s1 = "<CreationDate>2024-"
      $s2 = "<LastLoginDate>0001-01-01T00:00:00</LastLoginDate>"
   condition:
      filesize < 200KB
      and all of them
      and filepath contains "\\ScreenConnect\\App_Data\\"
}

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

542b11d0-63c8-4895-9d8a-5cd07dfdf374

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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

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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.

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

[[ currentRule.title ]]

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