PDF malware analysis — malicious · 149160b9b33b7d0b

MALICIOUS

PDF

45.8 KB

MD5: a8e516516945b061f16c659307043001 SHA-1: 3c84fd5a8b332dc22c8bffbc535be68f1b33ce77 SHA-256: 149160b9b33b7d0bf1cf9fccb3aef7c3fb299f364ee7ba9080d2fd5453625248

126 Risk Score

Malware Insights

MITRE ATT&CK

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

The PDF sample contains embedded JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT', 'PDF_JS', and 'PDF_JS_EXPLOIT_CLUSTER'. The deobfuscated JavaScript code appears to be designed to execute arbitrary code, likely downloading and executing a second-stage payload. The presence of XFA forms and the use of String.fromCharCode further support the exploitation of PDF vulnerabilities. While the exact payload is not discernible, the overall pattern suggests a malicious document used for initial compromise.

Machine Learning

Nyx PDF Classifier malicious score 0.9999

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.
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.
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.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 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0012_000.js` `df4a21ca9c08789284b6ea66b46fc83a30f8c70b7473fe9e59c694f6980b3b89`	pdf-javascript-stream	PDF /JS object 12 at offset 0xA0B7	4881 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
`legacy_pdfkit_stage_000.js` `a7e4d2ac955fe5e4ecd42e062ca8730dbb18f316e0b96d59466aec05ac33c44f`	deobfuscated-js	split-join delimiter stripped JavaScript at offset 0xA0F9	4667 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 6 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
`font_00_sfnt_off0000033c.bin` `c3cbc576fb471b8bbd3e40c7ead09529e4f5f425f26257513aa444abaec5d5fc`	pdf-font-stream	PDF embedded font (sfnt) at offset 0x33C	65932 bytes

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