PDF malware analysis — malicious · 16a62fed5c72ab6f

MALICIOUS

PDF

20.7 KB

MD5: 24743e487d193fbbf6cc6e2d33f20947 SHA-1: 8e695d6818a24e756f725d39ff5340675dc89564 SHA-256: 16a62fed5c72ab6fb7265c2348564633ca7ab273dcd1b555b64c3774c46d7ff8

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 uses String.fromCharCode to construct its payload. This JavaScript is flagged as an exploit cluster, indicating it's designed to execute arbitrary code. The primary function of this script appears to be downloading and executing a second-stage payload, as suggested by the obfuscated string construction and the ML classifier's high confidence in maliciousness. The benign URL found is not considered a threat.

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#

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0099_000.js` `cb5ef550ce97c0659cbb358c1a0bfb464ac085b9c4aa0d27c3a98eee4e4bf901`	pdf-javascript-stream	PDF /JS object 99 at offset 0x479A	20000 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).

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