Malicious PDF — malware analysis report

Static analysis result for SHA-256 66b904f5064098a2…

MALICIOUS

PDF

10.2 KB Authoring application: Gobfnyrjjqvpzyw Nlkgrkiztiix First seen: 2026-05-07
MD5: 0bb95efa38573cd33af47cf01743874e SHA-1: 720d3d7f1e9ba842bd4775cabe15a9562b8be686 SHA-256: 66b904f5064098a2860ed2ca4fb2a13401f33c667b53b298e65f80c06b44c48d
72 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

This PDF file contains a malformed stream length, indicating an attempt to hide malicious content. The ML classifier strongly flagged it as malicious. Embedded JavaScript, likely responsible for downloading a second-stage payload from the unknown URL, is present within the malformed stream.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • 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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • Embedded script payload in PDF stream info PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain an HTML/XFA <script> tag without accompanying Windows shell-execution primitives — common in accessible XFA forms but worth surfacing for analyst review.
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www1.thebestcguard.uni.me/?qtmswi=ldfa17TO7M2L187XsZidrJiY2OXgqqmooKmbmMSdo6TEjenUr5WkpqWrrJmpnpqI0eaxlJelmZjF09bfsMm9v47Vy8mwp4namQ%3D%3D&quot;;var In PDF document text
    • http://www1.thebestcguard.uni.me/?qtmswi=ldfa17TO7M2L187XsZidrJiY2OXgqqmooKmbmMSdo6TEjenUr5WkpqWrrJmpnpqI0eaxlJelmZjF09bfsMm9v47Vy8mwp4namQ%3D%3D&quotIn PDF document text
    • http://ns.adobe.com/xdp/In PDF document text
    • http://www.xfa.org/schema/xci/1.0/In PDF document text
    • http://www.xfa.org/schema/xfa-template/2.5/In PDF document text
    • http://ns.adobe.com/xtd/In PDF document text
    • http://www.xfa.org/schema/xfa-data/1.0/In PDF document text
    • http://ns.adobe.com/xfdf/In PDF document text
    • http://www.xfa.org/schema/xfa-form/2.8/In PDF document text

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0008.bin pdf-embedded-file PDF EmbeddedFile object 8 at offset 0x207 9340 bytes
SHA-256: 84aff9a386bd371dd100aff47d8a13927526543165c5b17dc4b9f03ac639a172
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 long base64-like blob(s).

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