Malicious PDF — malware analysis report

Static analysis result for SHA-256 c5b1a4dc9ff9bb93…

MALICIOUS

PDF

115.9 KB Created: 2016-04-23 00:16:36 -04:00
MD5: 395aae19e0c75bb3dfb57942075a4713 SHA-1: ca619e39bed9fd0696bc64d27aeca5b1a0188896 SHA-256: c5b1a4dc9ff9bb93bf21f48abd1484b1dcb9f715e916a36e7c4bcb864b468dfb
258 Risk Score

Malware Insights

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

This PDF file contains XFA form elements with embedded JavaScript, which is a known vector for exploiting vulnerabilities in PDF readers. The 'XFA_HEAP_SPRAY' heuristic indicates the presence of exploit code designed to trigger a heap spray. The ML classifier and ClamAV detection strongly suggest malicious intent, likely to download and execute a secondary payload. No specific family could be identified.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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/
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://purl.org/dc/elements/1.1/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_pdf_script_000002bb.bin
0d7f174bdabc3fe4d1fa202676ddeaff81a8485b35f46e2c968ca1d1eda789b7		 pdf-embedded-script PDF raw stream script payload at offset 0x2BB 114262 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).

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