Malicious PDF — malware analysis report

Static analysis result for SHA-256 7d8c6c3e3b98100c…

MALICIOUS

PDF

11.9 KB
MD5: 438aec0d6499fc6f6e7e51b1bdc65647 SHA-1: 9578fe0f3ffe3694b8cf8ccd4308c01f1dcb01aa SHA-256: 7d8c6c3e3b98100cd5767bcf4a4df24dafa5e5c510405796a7b78f0be7e5cf56
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript T1204.002 Malicious File

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT' and 'PDF_JS'. Critical heuristics like 'PDF_ANNOT_SUBJECT_MARKER_EVAL_STAGER' and 'CVE_2007_5659' point to the exploitation of a known PDF vulnerability (CVE-2007-5659) using a stager that decodes and evaluates JavaScript from the annotation subject. The presence of deobfuscated JavaScript files ('legacy_pdfkit_stage_000.js', 'legacy_pdfkit_stage_001.js') suggests a multi-stage attack, common for downloading and executing further malicious content. ClamAV also identified the file as 'Pdf.Exploit.Agent-36065'.

Heuristics 7

  • Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659
    PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
  • Annotation subject percent-decoding eval stager critical PDF_ANNOT_SUBJECT_MARKER_EVAL_STAGER
    OpenAction JavaScript forces annotation enumeration, reads an annotation /Subject payload with getAnnots(), rewrites marker bytes into percent escapes, decodes it with unescape(), and dispatches it through eval. This is a high-confidence exploit-kit staging pattern. It is intentionally not mapped to CVE-2009-1492 unless getAnnots() itself carries the crafted integer or long argument shape for that vulnerability.
  • ClamAV: Pdf.Exploit.Agent-36065 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36065
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser exited 1. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
9c67560e8c63b720885d3efc1627b844b86a6ec08e99e5b65a22eae832045756
pdf-javascript-stream PDF /JS object 7 at offset 0x19C 431 bytes
legacy_pdfkit_stage_000.js
9e08804b84e47fa849c7b278c57c72bdccf8b631f61a080963e9585ed285cda9
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x315 12167 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
legacy_pdfkit_stage_001.js
9cd45f3a569412ddf435d1f801e3a1356b520b628c2d175da3ea7f4f9850b754
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x315 5022 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).