PDF malware analysis — malicious · 4f3fe77bafa2020f

MALICIOUS

PDF

23.6 KB

MD5: ba076b2e2b6c8f323d00a599bb8c88ae SHA-1: b39d29778fa68e23070458f121f143275c84cbcc SHA-256: 4f3fe77bafa2020f2c884c878ee1ba47548bc006b363c8817903957cea50a8fe

120 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

The PDF contains embedded JavaScript, flagged by multiple heuristics as a PDF JavaScript exploit cluster. The ML classifier also strongly indicates maliciousness. The deobfuscated JavaScript appears to be responsible for downloading and executing a second-stage payload, as indicated by the presence of obfuscated code and the nature of the extracted artifacts. The specific URLs found are benign, but the JavaScript itself is the primary indicator of malicious activity.

Machine Learning

Nyx PDF Classifier malicious score 0.9994

Heuristics 7

PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER

PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
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 paints image(s) but contains no text operators info PDF_IMAGE_ONLY_LURE

PDF has 1 image XObject(s) and the content stream contains no text-emitting operators (BT/ET, Tj, TJ, ', ") in either raw bytes or decompressed streams — this is the screenshot-as-PDF pattern used to bypass text-based scanners and to deliver instructions purely through rendered pixels. It is informational unless paired with invisible links or risky URI context.
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.
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
URL http://www.w3.org/1999/02/22-rdf-syntax-ns#
- http://ns.adobe.com/xap/1.0/
- http://purl.org/dc/elements/1.1/
- http://ns.adobe.com/xap/1.0/mm/
- http://ns.adobe.com/pdf/1.3/

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0099_000.js` `5a50e051ffc3a1348a6561389eb56acda9d9d80a3b6f5e61c8b97df1a3dce9f1`	pdf-javascript-stream	PDF /JS object 99 at offset 0x548D	8609 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 9 long base64-like blob(s).
`deobfuscated.js` `dd81b745dc824305334bd88d7444674da1ef75c29a690bd498ee79d1b4f9f69e`	deobfuscated-js	PDF JavaScript deobfuscation pass	39956 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 18 long base64-like blob(s).

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