PDF malware analysis — malicious · b9b8e551990f8e36

MALICIOUS

PDF

15.1 KB Created: 2009-09-25 19:41:98 Authoring application: PDF Library 7.3.5 (via PDF Library 10.10.7)

MD5: 33dd9246821cb59bb1c7fd991d143e52 SHA-1: 83f9c18aaccbb9cccdb25dd97ff25e833584a264 SHA-256: b9b8e551990f8e36ae11ca9cba5989a2357ed47dab4ec735048a1a96130bb4f1

118 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1059.007 JavaScript

This PDF file was flagged as malicious by an ML classifier with high confidence. Static analysis detected embedded JavaScript, including obfuscated code utilizing eval() and String.fromCharCode. The presence of these JavaScript actions and streams, combined with the ML classification, strongly suggests the PDF is designed to download and execute a secondary payload. No specific family could be identified.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 7

eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
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.
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)
PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED

The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PSSyntaxError. 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 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0007_000.js` `40c6e82e6acf425be339e1058db7b088fc3a6bda65d6ea323e65697459501199`	pdf-javascript-stream	PDF /JS object 7 at offset 0x268	132326 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).

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