Malicious PDF — malware analysis report

Static analysis result for SHA-256 238f4f37e50d767a…

MALICIOUS

PDF

52.6 KB Created: 2017-11-13 00:16:14 +01:00
MD5: 06cd1ea7cd1bea155b6bdea431cce396 SHA-1: e05af278113f9ba46c6a2171d5fe1b0f2a24f1f1 SHA-256: 238f4f37e50d767a57f2f95c8a63f708af2a12013b3daa9cd5ea1c790e825b41
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

This PDF file was flagged as malicious by ClamAV with the signature Pdf.Dropper.Agent-7239485-0. Static analysis revealed embedded JavaScript, including an eval() call and String.fromCharCode usage, indicating obfuscated code execution. The presence of an embedded script payload further supports its role as a dropper. The benign URLs extracted are likely unrelated to the malicious functionality.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9918

Heuristics 11

  • ClamAV: Pdf.Dropper.Agent-7239485-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-7239485-0
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • Embedded script payload in PDF stream medium PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain an HTML/XFA <script> tag without accompanying Windows shell-execution primitives — common in accessible XFA forms but worth surfacing for analyst review.
  • 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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • AcroForm button with action trigger low PDF_ACROFORM_BUTTON
    PDF contains a /Btn form field together with a SubmitForm/URI/Launch/JS trigger — this is the building block of fake 'Download' or 'Open' button overlays used in PDF phishing lures
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://purl.org/dc/elements/1.1/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0029.bin
ddb2f0273ff53a78cba698afed0c23add8e219eaa85fecd99611493bebdb4d27		 pdf-embedded-file PDF EmbeddedFile object 29 at offset 0xC5BD 1237 bytes
javascript_obj0001_000.js
fa64b4b18bae88a35a311c66e2da3b8e533af452982f59d90014b76eec69b141		 pdf-javascript-stream PDF /JS object 1 at offset 0x3EE 210 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).

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