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CWE WEAKNESSES  /  CWE-602

CWE-602

Client-Side Enforcement of Server-Side Security

Class EXPLOIT LIKELIHOOD: MEDIUM

What it is

The product is composed of a server that relies on the client to implement a mechanism that is intended to protect the server.

When the server relies on protection mechanisms placed on the client side, an attacker can modify the client-side behavior to bypass the protection mechanisms, resulting in potentially unexpected interactions between the client and server. The consequences will vary, depending on what the mechanisms are trying to protect.

Impact

Access Control, AvailabilityBypass Protection Mechanism, DoS: Crash, Exit, or Restart
Access ControlBypass Protection Mechanism, Gain Privileges or Assume Identity

Mitigations

  • [Architecture and Design]For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.Even though client-side checks provide m
  • [Architecture and Design] If some degree of trust is required between the two entities, then use integrity checking and strong authentication to ensure that the inputs are coming from a trusted source. Design the product so that this trust is managed in a centralized fashion, especially if there are complex or numerous communication channels, in order to reduce the risks that the implementer will mistakenly omit a check in

Real-world CVE examples

  • CVE-2024-50653 — Chain: e-commerce product has a "front-end restriction" for coupon use (CWE-602), but the server does not restrict the number of requests for the same coupon (C
  • CVE-2022-33139 — SCADA system only uses client-side authentication, allowing adversaries to impersonate other users.
  • CVE-2006-6994 — ASP program allows upload of .asp files by bypassing client-side checks.
  • CVE-2007-0163 — steganography products embed password information in the carrier file, which can be extracted from a modified client.
  • CVE-2007-0164 — steganography products embed password information in the carrier file, which can be extracted from a modified client.
  • CVE-2007-0100 — client allows server to modify client's configuration and overwrite arbitrary files.

Related weaknesses

Test & detect

Browse all common weaknesses, check related exploited CVEs, or map to ATT&CK techniques.

Source: MITRE CWE. View on cwe.mitre.org →

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