Malicious PDF — malware analysis report

Static analysis result for SHA-256 186683a87f0d77cf…

MALICIOUS

PDF

24.5 KB
MD5: f874620a28a7d2a20268f9c75077a808 SHA-1: 66bdf99464985089a8adb0df8f10d7b5b98e78ce SHA-256: 186683a87f0d77cf3df872ed6c73a178373a904f1cb9909d6d1178b0bf48afca
206 Risk Score

Malware Insights

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

The PDF document contains XFA forms and embedded scripts, with heuristics indicating the use of JavaScript and potential unescaping of code. The ML classifier and ClamAV detection strongly suggest malicious intent, likely to exploit vulnerabilities and execute a payload. An embedded file artifact was also identified.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • XFA form contains risky executable script high CVE related PDF_XFA_SCRIPT
    PDF embeds an XFA form whose script block contains exploit, submission/launch, or shell-execution primitives. Ordinary LiveCycle print/update scripts are left as generic XFA/JS signals unless stronger behavior is present.
  • ClamAV: Pdf.Malware.Agent-9809494-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Malware.Agent-9809494-0
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits
  • 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
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules.
  • Embedded script payload in PDF stream low 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://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xfa-template/2.5/
    • http://www.xfa.org/schema/xfa-data/1.0/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0008.bin
19912cdadc8a031c23f27057c17a2ae0f3d9b1ac4b5e7e0adbc558334993bdfd		 pdf-embedded-file PDF EmbeddedFile object 8 at offset 0xD1 24342 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).

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