Malicious PDF — malware analysis report

Static analysis result for SHA-256 5fe50bd215643432…

MALICIOUS

PDF

9.5 KB
MD5: eee85f5b4130951bc6240aa1edbae432 SHA-1: 8e1c26aebec8cf5fee1840c47658bb4210565432 SHA-256: 5fe50bd21564343234e259f5ebfaf008584b9c91fb7b3f1a75afa34ed2fc4dde
146 Risk Score

Malware Insights

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

The PDF file utilizes XFA forms and embedded JavaScript to achieve code execution. The deobfuscated JavaScript contains a function 'hx' that decodes a hex-encoded string by subtracting 60 from each byte's integer value. This decoded string is then passed to 'eval()', indicating the execution of a second-stage payload. The embedded file 'embedded_file_obj0041.bin' is likely this payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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.
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • 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.
  • 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/xci/1.0/
    • http://www.xfa.org/schema/xfa-template/2.4/
    • http://www.xfa.org/schema/xfa-data/1.0/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0041.bin
1741dba90bffc453757e11f0ed88c77bbf7c1fe5905e35b866a07d2c20ecfad2
pdf-embedded-file PDF EmbeddedFile object 41 at offset 0x52 1165 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
deobfuscated.js
a816900ed9eecb85aafd82c2772680a1303d44e00977fb1912def2f77902728d
deobfuscated-js PDF JavaScript deobfuscation pass 1871 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).