CVE-2020-36851
CriticalSummary
Cors-anywhere instances configured as open proxies allow unauthenticated external users to induce the server to make HTTP requests to arbitrary targets (SSRF). Attackers can access internal endpoints and metadata services, leading to credential theft and unauthorized access to internal services.
Risk Assessment
This vulnerability poses a serious risk to organizations, enabling attackers to steal cloud credentials and execute remote code, potentially leading to full compromise of cloud resources.
Recommendation
It is recommended to restrict access to cors-anywhere instances and implement appropriate security measures to prevent unauthorized requests and exploitation of this vulnerability.
Original NVD description (English source)
Rob--W cors-anywhere instances configured as an open proxy allow unauthenticated external users to induce the server to make HTTP requests to arbitrary targets (SSRF). Because the proxy forwards requests and headers, an attacker can reach internal-only endpoints and link-local metadata services, retrieve instance role credentials or other sensitive metadata, and interact with internal APIs and services that are not intended to be internet-facing. The vulnerability is exploitable by sending crafted requests to the proxy with the target resource encoded in the URL; many cors-anywhere deployments forward arbitrary methods and headers (including PUT), which can permit exploitation of IMDSv2 workflows as well as access to internal management APIs. Successful exploitation can result in theft of cloud credentials, unauthorized access to internal services, remote code execution or privilege escalation (depending on reachable backends), data exfiltration, and full compromise of cloud resources.