PDF malware analysis — malicious · 79a8493d680a7e91

MALICIOUS

PDF

23.6 KB

MD5: 6bf037fe727262fc7b91c493d021da6a SHA-1: a1b198f5dba4b6c4ba225c07655bf3102e9d67cf SHA-256: 79a8493d680a7e91eaf107d0b2c5b23545d81f05431d76a9d46e650454b216ab

120 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript, which is heavily obfuscated and utilizes String.fromCharCode, indicating an attempt to hide malicious code. This JavaScript is likely responsible for downloading and executing a second-stage payload, as suggested by the 'PDF JavaScript exploit cluster' heuristic. The ML classifier strongly flags this PDF as malicious, supporting the conclusion that it is designed for exploitation.

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` `ff953c35fbb530d7a9d8626c22ac23578752d00ffa121d91e506667ca49289c2`	pdf-javascript-stream	PDF /JS object 99 at offset 0x548D	8597 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` `510fea13ae9834b56415f6f3a4da67c0554d66de7733e574fdbc1e7fb30efd9b`	deobfuscated-js	PDF JavaScript deobfuscation pass	40182 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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