Malicious PDF — malware analysis report

Static analysis result for SHA-256 31ec0467ceb64c40…

MALICIOUS

PDF

37.7 KB
MD5: 3769e05566b99a0a303563ea1e259161 SHA-1: ad2dee4aff307ac626adfcd8da50d1bfb53fbb27 SHA-256: 31ec0467ceb64c40cb3d1f7bb6973820958453a9be99a16ac5146b15709c496f
124 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment

This PDF file contains embedded JavaScript and a Flash object, indicating a likely exploit attempt. The ML classifier strongly suggests maliciousness. The embedded JavaScript, named 'javascript_obj0006_000.js', is highly suspicious and likely responsible for initiating the malicious activity, potentially downloading and executing a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • 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
  • 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.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
Adobe.swf
ce5f7936cf8e3536a88a804ce2d6902022df1794fa878bdc64a26866e34ba989
pdf-embedded-file PDF EmbeddedFile object 16 at offset 0xACB 55839 bytes
javascript_obj0006_000.js
8ab00533b0fa52648f07d7e2a297cac33c8f33dc1f44d59847f69e4665a565f4
pdf-javascript-stream PDF /JS object 6 at offset 0xF5 1582 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).