PDF malware analysis — malicious · 1f9f0d59f7cbaeba

MALICIOUS

PDF

4.0 KB

MD5: efa247a161772dc884eabfe5330f6cc9 SHA-1: fd026eff797abfa2448319ec17a15745c48a9ddb SHA-256: 1f9f0d59f7cbaeba5d6d38da8930e8ae22f998bef19d97aab2047ddbc3fb28f1

96 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The ML classifier strongly flagged this PDF as malicious. The presence of `eval()` and `String.fromCharCode` within the JavaScript streams suggests obfuscation and dynamic code execution. The deobfuscated JavaScript file 'acroform_b64_00.js' is likely responsible for downloading and executing a second-stage payload, a common technique for malware delivery.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 5

eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
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)
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.

Filename	Kind	Source	Size
`javascript_obj0013_001.js` `62487a22365df79f84b8e2b11eadf82ecc255d598aeba2550fd25815dfb55da1`	pdf-javascript-stream	PDF /JS object 13 at offset 0x368	6357 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
`acroform_b64_00.js` `21b791a0f5e4df0afd04039041eba9d5ce0bb180215ba258beb81d14e5ed2998`	deobfuscated-js	PDF AcroForm base64 (decompressed) at offset 0x99D	3614 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).

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