PDF malware analysis — malicious · b3aa55c86851fb71

MALICIOUS

PDF

3.7 KB

MD5: fc45648e952c476400824b4654e9b2be SHA-1: 5c71718fa0c8af51f4f4d1f8805f4b7aa9e5f49f SHA-256: b3aa55c86851fb7147fc4c10dc485d4c02645e65f638c65ff60f68aa22e9cda3

152 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 JavaScript/Script Execution T1204.002 Malicious File

This PDF contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The presence of an eval() call and String.fromCharCode() within the decoded stream suggests obfuscated code execution. The ML classifier strongly flags this PDF as malicious. The embedded 'test.swf' file and RichMedia (Flash) heuristic further indicate a multi-stage attack, likely involving the execution of the JavaScript to download and run a secondary payload.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 8

RichMedia (Flash) high PDF_RICHMEDIA

PDF contains /RichMedia (Adobe Flash) which is a historic exploit vector
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.
Embedded file low PDF_EMBEDDED

PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
XFA form low PDF_XFA

PDF uses XML Forms Architecture — can contain script logic
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_obj0006_000.js` `825b7eb461574e06a628cc6718f69e7e5b3cf8fcae6b39399c0f883366eafea3`	pdf-javascript-stream	PDF /JS object 6 at offset 0x226	8852 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`stream_000_off0000012f.bin` `2f8c75f2e9f3e540017d7333425c297887fb0cf44b2c4fbe17b9186842df87a2`	decompressed-pdf-stream	PDF FlateDecoded stream at offset 0x12F	379 bytes

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