2021-32777 | Envoy ext-authz Extension authorization
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A vulnerability, which was classified as critical, was found in Envoy up to 1.16.4/1.17.3/1.18.3/1.19.0. This affects an unknown part of the component ext-authz Extension. The manipulation with an unknown input leads to a privilege escalation vulnerability. CWE is classifying the issue as CWE-863. This is going to have an impact on confidentiality. The summary by CVE is:
Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions when ext-authz extension is sending request headers to the external authorization service it must merge multiple value headers according to the HTTP spec. However, only the last header value is sent. This may allow specifically crafted requests to bypass authorization. Attackers may be able to escalate privileges when using ext-authz extension or back end service that uses multiple value headers for authorization. A specifically constructed request may be delivered by an untrusted downstream peer in the presence of ext-authz extension. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes to the ext-authz extension to correctly merge multiple request header values, when sending request for authorization.
The weakness was presented 08/25/2021. It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2021-32777 since 05/12/2021. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available.
Upgrading to version 1.16.5, 1.17.4, 1.18.4 or 1.19.1 eliminates this vulnerability. The upgrade is hosted for download at envoyproxy.io.
VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1
Status: Not defined
0-Day Time: 🔒
Upgrade: Envoy 1.16.5/1.17.4/1.18.4/1.19.1
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