Sync from PR#2310

Update attachment_pdf_extortion_leveraging_breach_data.yml by @morriscode
#2310
Source SHA aedb24f
Triggered by @morriscode

detection-rules/attachment_pdf_extortion_leveraging_breach_data.yml

@@ -0,0 +1,75 @@
+name: "Extortion / Sextortion - PDF attachment leveraging breach data from freemail sender"
+description: "Detects sextortion attempts leveraging breach data, including names, addresses, phone numbers and frequently using Google Maps/Bing Maps streetview images to bolster confidence and fear."
+type: "rule"
+severity: "high"
+source: |
+  type.inbound
+
+  // sender is a freemail domain
+  and sender.email.domain.root_domain in $free_email_providers
+
+  // attachment filename is the same as the subject
+  and any(attachments,
+          (
+            strings.ilevenshtein(strings.concat(subject.subject,
+                                                ".",
+                                                .file_extension
+                                 ),
+                                 .file_name
+            ) <= 1
+          )
+          or strings.contains(.file_name, subject.subject)
+  )
+
+  // body contains a US address, or the body is the subject
+  and (
+    regex.icontains(body.current_thread.text,
+                    '\d+\s[\w\s.]+(?:\n)?[\w\s]+\s[A-Z]{2}\s\d{5}(?:-\d{4})?(?:\n)?|\d+\s[\w\s.]+(?:Street|St|Avenue|Ave|Boulevard|Blvd|Road|Rd|Drive|Dr|Lane|Ln|Court|Ct|Way|Place|Pl|Terrace|Ter|Circle|Cir|Parkway|Pkwy|Trail|Trl|Highway|Hwy|Loop)\b\.?',
+                    // a Canadian address
+                    '\d+\s[\w\s.]+(?:\n)?[\w\s]+\s((?:Ontario|ON)|(?:Quebec|QC)|(?:Nova Scotia|NS)|(?:New Brunswick|NB)|(?:Manitoba|MB)|(?:British Columbia|BC)|(?:Prince Edward Island|PEI?)|(?:Saskatchewan|SK)|(?:Alberta|AB)|(?:Newfoundland and Labrador|NL)|(?:Yukon|YT)|(?:Northwest Territories|NT)|(?:Nunavut|NU))\s*[ABCEGHJ-NPRSTVXY]\d[ABCEGHJ-NPRSTV-Z][ -]?\d[ABCEGHJ-NPRSTV-Z]\d'
+    )
+    or subject.subject == body.current_thread.text
+  )
+
+  // there's a PDF attachment with an image at a depth of one, measuring 148x148 and containing a QR code that is a BTC address
+  and any(attachments,
+          .file_type == "pdf"
+          and any(file.explode(.),
+                  (
+                    (.depth == 1 and .flavors.mime == "image/jpeg")
+                    and (
+                      .scan.exiftool.image_height == 148
+                      and .scan.exiftool.image_width == 148
+                      and regex.match(.scan.qr.data,
+                                      '(1[a-km-zA-HJ-NP-Z1-9]{25,34}|3[a-km-zA-HJ-NP-Z1-9]{25,34}|bc1[qp-z0-9]{39,59})'
+                      )
+                    )
+                  )
+                  or (
+                    any(.scan.strings.strings,
+                        regex.icontains(.,
+                                        'Amount(?:\s*\w+){0,3}\s*:?\s*(?:USD\s*)?(?:\$\s?\d+|\d+\s?\$?)'
+                        )
+                    )
+                    and any(.scan.strings.strings,
+                            regex.icontains(.,
+                                            '(\bBITCOIN\b|\bBTC\b|\bLTC\b|Wallet)'
+                            )
+                    )
+                  )
+          )
+  )
+attack_types:
+  - "BEC/Fraud"
+tactics_and_techniques:
+  - "Free email provider"
+  - "PDF"
+  - "Social engineering"
+  - "QR code"
+detection_methods:
+  - "Content analysis"
+  - "File analysis"
+  - "QR code analysis"
+id: "efb5a213-df55-5ddc-a300-ad3a6da8e74e"
+testing_pr: 2310
+testing_sha: aedb24f0f031de4a17fa9308c489db85269b522f