CVE Vulnerabilities

CVE-2021-39243

Cross-Site Request Forgery (CSRF)

Published: Aug 23, 2021 | Modified: Aug 26, 2021
CVSS 3.x
6.5
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
CVSS 2.x
4.3 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:N
RedHat/V2
RedHat/V3
Ubuntu

Cross-Site Request Forgery (CSRF) exists on Altus Nexto, Nexto Xpress, and Hadron Xtorm devices via any CGI endpoint. This affects Nexto NX3003 1.8.11.0, Nexto NX3004 1.8.11.0, Nexto NX3005 1.8.11.0, Nexto NX3010 1.8.3.0, Nexto NX3020 1.8.3.0, Nexto NX3030 1.8.3.0, Nexto NX5100 1.8.11.0, Nexto NX5101 1.8.11.0, Nexto NX5110 1.1.2.8, Nexto NX5210 1.1.2.8, Nexto Xpress XP300 1.8.11.0, Nexto Xpress XP315 1.8.11.0, Nexto Xpress XP325 1.8.11.0, Nexto Xpress XP340 1.8.11.0, and Hadron Xtorm HX3040 1.7.58.0.

Weakness

The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.

Affected Software

Name Vendor Start Version End Version
Nexto_nx3003_firmware Altus 1.8.11.0 (including) 1.8.11.0 (including)

Potential Mitigations

  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
  • For example, use anti-CSRF packages such as the OWASP CSRFGuard. [REF-330]
  • Another example is the ESAPI Session Management control, which includes a component for CSRF. [REF-45]
  • Use the “double-submitted cookie” method as described by Felten and Zeller:
  • When a user visits a site, the site should generate a pseudorandom value and set it as a cookie on the user’s machine. The site should require every form submission to include this value as a form value and also as a cookie value. When a POST request is sent to the site, the request should only be considered valid if the form value and the cookie value are the same.
  • Because of the same-origin policy, an attacker cannot read or modify the value stored in the cookie. To successfully submit a form on behalf of the user, the attacker would have to correctly guess the pseudorandom value. If the pseudorandom value is cryptographically strong, this will be prohibitively difficult.
  • This technique requires Javascript, so it may not work for browsers that have Javascript disabled. [REF-331]

References