PDF malware analysis — malicious · bcf5450526e97d19

MALICIOUS

PDF

17.3 KB

MD5: 85eeaa590af7bc19bedd99a325dcce08 SHA-1: b57a093e4447c4d75580631f9895c7b3141adb35 SHA-256: bcf5450526e97d193a92285db9c23f4e6017152182e2939e16cbc47db54808fa

66 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1059.007 JavaScript

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT, PDF_JS, and PDF_EVAL. The presence of 'eval()' and 'String.fromCharCode' suggests obfuscation. The extracted JavaScript files, particularly 'legacy_pdfkit_stage_000.js', are likely responsible for downloading and executing a secondary payload. The obfuscation and the nature of the extracted scripts point towards a downloader or droppper functionality.

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_obj0004_000.js` `f319057e1fa731a630869eaf54793121e7fafce165bad6b2dd37afb996613727`	pdf-javascript-stream	PDF /JS object 4 at offset 0xE1	315 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_000.js` `43b350f3c8a4f8e3d82f348723ac8b82b1a393be9b2444fa115bedcc61b69ed5`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1CA9	12358 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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