CVE-2013-2157 in Keystone
Summary
by MITRE
OpenStack Keystone Folsom, Grizzly before 2013.1.3, and Havana, when using LDAP with Anonymous binding, allows remote attackers to bypass authentication via an empty password.
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Analysis
by VulDB Data Team • 01/04/2022
The vulnerability identified as CVE-2013-2157 represents a critical authentication bypass flaw within OpenStack Keystone authentication service. This issue specifically affects Keystone versions released under the Folsom, Grizzly, and Havana release cycles prior to the 2013.1.3 update. The vulnerability stems from improper handling of LDAP authentication when anonymous binding is enabled, creating a security loophole that allows malicious actors to circumvent the authentication process entirely.
The technical root cause of this vulnerability lies in the LDAP authentication implementation within Keystone's authentication framework. When Keystone is configured to use LDAP backend authentication with anonymous binding enabled, the system fails to properly validate authentication credentials. Attackers can exploit this weakness by submitting authentication requests with empty passwords, which the system incorrectly accepts as valid credentials. This behavior occurs because the LDAP library used by Keystone does not properly enforce password validation when anonymous binding is active, allowing empty password attempts to succeed in authentication attempts.
The operational impact of this vulnerability is severe and far-reaching within OpenStack environments. Remote attackers who can reach the Keystone service can bypass authentication entirely without requiring valid credentials, effectively granting them unrestricted access to the entire OpenStack cloud infrastructure. This authentication bypass enables attackers to perform any action within the cloud environment, including creating new users, accessing virtual machines, manipulating storage resources, and potentially escalating privileges to administrative levels. The vulnerability is particularly dangerous because it allows attackers to exploit the system from external networks without requiring prior access or knowledge of legitimate credentials.
This vulnerability maps directly to CWE-287, which addresses improper authentication issues in software systems. The flaw represents a classic case of weak credential validation where the system fails to properly verify authentication credentials, allowing empty or null values to be accepted as valid. From an adversary perspective, this vulnerability aligns with ATT&CK technique T1078.004, which covers legitimate credentials gained through exploitation of weak authentication mechanisms. The attack surface is particularly broad since Keystone serves as the central authentication point for all OpenStack services, making this vulnerability a critical entry point for attackers seeking to compromise entire cloud environments.
Organizations affected by this vulnerability should immediately implement mitigations including updating to Keystone versions 2013.1.3 or later where the issue has been resolved. The primary remediation involves disabling anonymous LDAP binding when using Keystone with LDAP backends, as this configuration is inherently insecure and should not be used in production environments. Additionally, organizations should implement network-level restrictions to limit access to Keystone services to trusted networks only, and should conduct thorough security assessments of their LDAP configurations to ensure proper authentication enforcement. System administrators should also consider implementing additional monitoring and logging mechanisms to detect unauthorized authentication attempts that may indicate exploitation of this vulnerability.