CVE-2020-1677 in Mist Cloud UI
Summary
by MITRE • 10/17/2020
When SAML authentication is enabled, Juniper Networks Mist Cloud UI might incorrectly handle child elements in SAML responses, allowing a remote attacker to modify a valid SAML response without invalidating its cryptographic signature to bypass SAML authentication security controls. This issue affects all Juniper Networks Mist Cloud UI versions prior to September 2 2020.
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Analysis
by VulDB Data Team • 11/20/2020
The vulnerability identified as CVE-2020-1677 represents a critical weakness in the SAML authentication implementation within Juniper Networks Mist Cloud UI systems. This flaw specifically manifests when SAML authentication is enabled, creating an avenue for remote attackers to manipulate SAML responses without breaking their cryptographic signatures. The vulnerability stems from improper handling of child elements within SAML response documents, which allows attackers to inject malicious content while maintaining the integrity of the digital signature. This weakness directly compromises the core security controls that SAML authentication is designed to enforce, potentially enabling unauthorized access to cloud resources and user accounts.
The technical nature of this vulnerability aligns with CWE-295, which addresses improper certificate validation, and more specifically with CWE-347, concerning improper validation of cryptographic signatures. The flaw operates at the SAML protocol level where the system fails to properly validate the structure and content of SAML response elements, particularly focusing on how child elements are processed. Attackers can exploit this by manipulating the SAML response payload, potentially injecting additional claims or modifying existing attributes while preserving the original signature, thereby bypassing authentication mechanisms that rely on SAML assertions for user verification.
From an operational perspective, this vulnerability presents significant risk to organizations utilizing Juniper Mist Cloud UI services, particularly those relying on SAML-based single sign-on implementations. The impact extends beyond simple authentication bypass, potentially enabling attackers to escalate privileges, access sensitive data, or perform unauthorized actions within the cloud environment. The vulnerability affects all versions prior to the September 2 2020 patch release, meaning organizations with older deployments remain exposed to potential exploitation. Given that SAML authentication is commonly used for enterprise environments and cloud services, the potential attack surface is substantial, particularly for organizations that have not yet applied the necessary security updates.
The mitigation strategy for CVE-2020-1677 requires immediate deployment of the security patch released by Juniper Networks on September 2 2020, which addresses the improper handling of child elements in SAML responses. Organizations should also implement additional monitoring and logging mechanisms to detect potential exploitation attempts, particularly focusing on unusual SAML response patterns or signature validation anomalies. Network security teams should review their SAML implementation configurations and ensure that proper signature validation is enforced at all levels of the authentication process. This vulnerability also highlights the importance of adhering to ATT&CK framework principles regarding credential access and privilege escalation, as the compromised authentication mechanism could enable attackers to move laterally within the network or access additional resources that rely on the same authentication infrastructure.