CVE-2021-43557: apache software foundation apache apisix Command Injection

Vulnerability summary

CVE-2021-43557 is a high (CVSS 7.5) Command Injection vulnerability in apache software foundation apache apisix. EPSS estimates a 12.94% chance of exploitation in the next 30 days, higher than 96.2% of scored vulnerabilities. 2 public exploits are recorded.

Timeline

1. 22-11-2021
   PublishedVulnerability first disclosed.
2. 04-08-2024
   Last modifiedVulnerability information updated.

Description

The uri-block plugin in Apache APISIX before 2.10.2 uses $request_uri without verification. The $request_uri is the full original request URI without normalization. This makes it possible to construct a URI to bypass the block list on some occasions. For instance, when the block list contains "^/internal/", a URI like `//internal/` can be used to bypass it. Some other plugins also have the same issue. And it may affect the developer's custom plugin.

• CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.