PDF malware analysis — malicious · 1655350709f2954c

MALICIOUS

PDF

35.2 KB

MD5: 61204c4c4ed213ba1796b62fda5ca296 SHA-1: b33a3b19888cd5eaeba711d61741d925d68a9bcb SHA-256: 1655350709f2954cea6ccd82b278d3dc6dd05d11e2cfe64492d3cc5a25b3e814

194 Risk Score

Malware Insights

MITRE ATT&CK

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

The PDF file contains embedded JavaScript and a Flash object, indicating an attempt to exploit vulnerabilities. The JavaScript uses String.fromCharCode to construct strings, a common obfuscation technique. The critical PDF JavaScript exploit cluster heuristic firing, along with the ML classifier, strongly suggests malicious intent. The embedded JavaScript likely downloads and executes a second-stage payload, as indicated by the obfuscated string construction and the presence of an embedded SWF file.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 10

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.
RichMedia (Flash) high PDF_RICHMEDIA

PDF contains /RichMedia (Adobe Flash) which is a historic exploit vector
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
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.
Embedded file low PDF_EMBEDDED

PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
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)
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://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
`Adobe.swf` `8f9c84c8c00bc62ae296a81fac6640aa852ea67548abc1bd639aa0da1a1696c4`	pdf-embedded-file	PDF EmbeddedFile object 16 at offset 0xE4F	27347 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.
`javascript_obj0006_000.js` `fc461eb5c8df6dc0f7daa9da41b53b01237b66b145dee68bc11c1fd1bd8b995f`	pdf-javascript-stream	PDF /JS object 6 at offset 0x105	10500 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).

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