PDF malware analysis — malicious · 04f913b4efd388fc

MALICIOUS

PDF

43.1 KB

MD5: 8772951dfb90effc6ea21859fb00eb70 SHA-1: 99508f400c8c2e7926bfe37b8564df21c6933eb9 SHA-256: 04f913b4efd388fca0a07908fd66fad388caa0363f793398cbad68eb46a6df8a

164 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 flagged as an exploit cluster. The JavaScript stream is heavily obfuscated but appears to be designed to download and execute a secondary payload. The presence of XFA forms and the use of `String.fromCharCode` are common indicators in malicious PDFs. The ML classifier strongly indicates maliciousness.

Machine Learning

Nyx PDF Classifier malicious score 0.9999

Heuristics 8

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.
ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX

Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
Suspicious extracted artifact medium 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.
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.
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)
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.bitstream.com
- http://ns.adobe.com/xdp/
- http://www.xfa.org/schema/xci/2.6/
- http://www.xfa.org/schema/xfa-template/2.6/

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0012_000.js` `6b0aae786f25a0e4dc2229f576332bd3198988c24790c55f42298aca7fc7ee3c`	pdf-javascript-stream	PDF /JS object 12 at offset 0xA0B2	3881 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 4 long base64-like blob(s). Carved artifact contains 4 long hex-escaped blob(s).
`font_00_sfnt_off0000033c.bin` `26f3e7c91c76e658576c1bbb605ddb8e33e657870ea2f8ad3b8fe8f80b303358`	pdf-font-stream	PDF embedded font (sfnt) at offset 0x33C	65932 bytes

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