Malicious PDF — malware analysis report

Static analysis result for SHA-256 b85cec5e7b08359c…

MALICIOUS

PDF

37.7 KB
MD5: 2bc5695613a2a3cf21594514e0c37317 SHA-1: f111ab0f51856ec59f83e68c39a66c5d1de20ac5 SHA-256: b85cec5e7b08359c789d7fd2da79716dc2af6020c686e4e9107668d609a112dd
126 Risk Score

Malware Insights

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

The PDF file exhibits multiple indicators of malicious activity, including embedded JavaScript and Flash content, and a high ML classifier score. The presence of a JavaScript stream, identified as 'javascript_obj0006_000.js', suggests an attempt to execute code. The embedded Flash object further increases the likelihood of exploit delivery. These elements combined point towards an attack pattern focused on exploiting vulnerabilities within the PDF reader or delivering a secondary malicious 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 0xAD1 55839 bytes
javascript_obj0006_000.js
80cfc1e9f47f7387c46d905c23a8b77fc1c047f1706a78596a6b02ee3ccad7d9
pdf-javascript-stream PDF /JS object 6 at offset 0xF5 1576 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).