In Spring Framework, versions 5.2.x prior to 5.2.3, versions 5.1.x prior to 5.1.13, and versions 5.0.x prior to 5.0.16, an application is vulnerable to a reflected file download (RFD) attack when it sets a “Content-Disposition” header in the response where the filename attribute is derived from user supplied input.

Specifically, an application is vulnerable when all of the following are true:

• The header is prepared with org.springframework.http.ContentDisposition.
• The filename is set via one of:
  • ContentDisposition.Builder#filename(String), or
  • ContentDisposition.Builder#filename(String, US_ASCII)
• The value for the filename is derived from user supplied input.
• The user supplied input is not sanitized by the application.
• The downloaded content of the response is injected with malicious commands by the attacker (see RFD paper reference for details).

An application is not vulnerable if any of the following is true:

• The application does not set a “Content-Disposition” response header.
• The header is not prepared with org.springframework.http.ContentDisposition.
• The filename is set via one of:
  • ContentDisposition.Builder#filename(String, UTF_8), or
  • ContentDisposition.Builder#filename(String, ISO_8859_1)
• The filename is not derived from user supplied input.
• The filename is derived from user supplied input but sanitized by the application.

• Spring Framework
  • 5.2.0 to 5.2.2
  • 5.1.0 to 5.1.12
  • 5.0.0 to 5.0.15

Users of affected versions should apply the following mitigation. 5.2.x users should upgrade to 5.2.3. 5.1.x users should upgrade to 5.1.13. 5.0.x users should upgrade to 5.0.16. No other steps are necessary.  Releases that have fixed this issue include:

• Spring Framework
  • 5.2.3
  • 5.1.13
  • 5.0.16

This issue was identified and responsibly reported by Roman Shalymov from EPAM.