Malicious PDF — malware analysis report

Static analysis result for SHA-256 12b4425b2c734e99…

MALICIOUS

PDF

134.0 KB
MD5: 0816f02631bb1679e833e9da6aeb9f20 SHA-1: bfe98c47794c3d1fdb3f1e991de9598c3d18431f SHA-256: 12b4425b2c734e99b080f433bbec1d51658db171b2c0df118bd50f416d1fff51
258 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

This PDF file contains XFA (XML Forms Architecture) content, which is known to be vulnerable to heap spray attacks. The embedded JavaScript, specifically the 'BucUzukole' function, appears to be designed to spray the heap with data, likely to facilitate the exploitation of a vulnerability. The 'ML_NYX_PDF_MALICIOUS' and 'CLAMAV_DETECTION' heuristics confirm the malicious nature of the file, with ClamAV identifying it as 'Pdf.Exploit.Agent-6136306-0'. The primary attack vector is the exploitation of a client-side vulnerability through the XFA form's scripting capabilities.

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.
  • XFA JavaScript heap-spray exploit code critical PDF_XFA_HEAP_SPRAY
    PDF contains XFA script content with heap-spray or shellcode-like JavaScript markers such as large encoded word sequences, util.pack, large arrays, or spray variable names. This is a weaponised Adobe Reader exploit pattern, not a normal interactive form.
  • ClamAV: Pdf.Exploit.Agent-6136306-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-6136306-0
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution
  • 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_pdf_script_00000295.bin
27f123c157c8a93a9cb66073c6be96547f257023c2440f9e879acf3b49fa90f9		 pdf-embedded-script PDF raw stream script payload at offset 0x295 136462 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).

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