Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4f9ee3a8b9bd7a2…

MALICIOUS

PDF

35.3 KB
MD5: c74e604cc7aaab41d0debe573542bc6f SHA-1: c05c9723cbb12cd538b3831dd45008f1f1ba8197 SHA-256: b4f9ee3a8b9bd7a28e6766d940bf8217b3a00321ecc0816f1f0369ce8ac9ce0b
132 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript T1559.002 Component Object Model

The PDF file exhibits multiple indicators of malicious activity, including embedded JavaScript and a Flash object (Adobe.swf). The presence of `String.fromCharCode` and ASCIIHexDecode filters suggests obfuscation techniques commonly used to hide malicious code. The ML classifier strongly flags this PDF as malicious. The embedded JavaScript stream, named 'javascript_obj0006_000.js', likely contains code to execute further actions, such as downloading additional payloads or exploiting vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • RichMedia (Flash) high PDF_RICHMEDIA
    PDF contains /RichMedia (Adobe Flash) which is a historic exploit vector
  • ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX
    Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
  • 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)
  • 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://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/2.6/
    • http://www.xfa.org/schema/xfa-template/2.6/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
Adobe.swf
8f9c84c8c00bc62ae296a81fac6640aa852ea67548abc1bd639aa0da1a1696c4
pdf-embedded-file PDF EmbeddedFile object 16 at offset 0xE7B 27347 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.
javascript_obj0006_000.js
6b3fed2864f327ea7fb0240abb5b0b273e3d28bcb140ab4385f266979d47d8b6
pdf-javascript-stream PDF /JS object 6 at offset 0x105 10566 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).