Malicious PDF — malware analysis report

Static analysis result for SHA-256 65cd610ecc773ada…

MALICIOUS

PDF

23.3 KB Authoring application: 42.141.63.126.104.82.71.126.104.80.72.154.145.132.147.92.70.70.90.133.142.145.71.136.92.79.90.136.91.126.104.80.77.139.132.141.134.147.135.90.136.74.92.81.72.154.129.92.126.104.80.77.146.148.129.146.1 (via 48.141.130.147.136.142.141.63.126.137.82.71.72.154.126.137.83.92.126.139.84.71.72.90.136.133.71.126.137.83.91.88.79.79.79.72.154.126.137.84.92.70.142.74.148.96.114.137.134.134.134.138.143.148.107.83.9)
MD5: d4393cd600781d62a92e50c8a5f7fccc SHA-1: 957157f4f23da63b414dcd6c7ec540ad6d61f70e SHA-256: 65cd610ecc773adadce3637f32812ff8f5a9424f04db02311d0318bae908dc7c
114 Risk Score

Malware Insights

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

The PDF file contains XFA form elements and embedded scripts, flagged as risky executable script. The ML classifier strongly indicates maliciousness. The presence of embedded files, particularly 'embedded_file_obj0043.bin', suggests the document is designed to deliver a secondary payload. The attack pattern likely involves exploiting a PDF vulnerability to run this script, which in turn would download and execute further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

Heuristics 8

  • 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.
  • 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. (matched inside decoded stream)
  • 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.
  • AcroForm button with action trigger low PDF_ACROFORM_BUTTON
    PDF contains a /Btn form field together with a SubmitForm/URI/Launch/JS trigger — this is the building block of fake 'Download' or 'Open' button overlays used in PDF phishing lures
  • 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://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/1.0/
    • http://www.xfa.org/schema/xfa-template/2.2/
    • http://www.xfa.org/schema/xfa-data/1.0/
    • http://www.xfa.org/schema/xfa-locale-set/2.1/

Extracted artifacts 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0041.bin
c06dcd026a7ea0536b63e07ce688691b585339a3ab7ff59065e546b56308c7bb		 pdf-embedded-file PDF EmbeddedFile object 41 at offset 0x39FD 85 bytes
embedded_file_obj0042.bin
b40a217a8d9b8d3671cc3874c550d30941b93ca6dde99995d43921dede579865		 pdf-embedded-file PDF EmbeddedFile object 42 at offset 0x3AAF 1183 bytes
embedded_file_obj0043.bin
f8f1835bfee99f1de38ba2d61f82060d16ad1cdadfc50fd6a03b4489ad79e01d		 pdf-embedded-file PDF EmbeddedFile object 43 at offset 0x3CFF 1718 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
embedded_file_obj0044.bin
3dd68f00f4fcb366a2a3a17c65cb2626eeddf5ea5713302d374310561d810169		 pdf-embedded-file PDF EmbeddedFile object 44 at offset 0x40C8 144 bytes
embedded_file_obj0045.bin
ce4a3f07835c725838e55947d6b1f21771e0ad8084ee86d0890ecc12bd5231fd		 pdf-embedded-file PDF EmbeddedFile object 45 at offset 0x418A 2427 bytes
font_00_cff_off0000455a.bin
062eede2d0cc5d3972869dc7e2f2f9f01d1d1b3756b715c8252f06948ce99ae2		 pdf-font-stream PDF embedded font (cff) at offset 0x455A 1192 bytes

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