CVE-2021-27795 in Fabric OS
Summary
by MITRE • 12/06/2023
Brocade Fabric OS (FOS) hardware platforms running any version of Brocade Fabric OS software, which supports the license string format; contain cryptographic issues that could allow for the installation of forged or fraudulent license keys. This would allow attackers or a malicious party to forge a counterfeit license key that the Brocade Fabric OS platform would authenticate and activate as if it were a legitimate license key.
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Analysis
by VulDB Data Team • 12/24/2023
The vulnerability identified as CVE-2021-27795 affects Brocade Fabric OS hardware platforms and represents a critical cryptographic weakness that undermines the integrity of the licensing system. This flaw specifically impacts systems that support the license string format, creating a pathway for adversaries to manipulate the authentication mechanisms that govern legitimate software activation. The vulnerability stems from insufficient cryptographic validation processes within the license key verification system, allowing attackers to generate and install counterfeit license keys that will be accepted by the platform as authentic. This represents a fundamental breakdown in the software's trust model and could enable unauthorized access to premium features and functionalities.
The technical implementation of this vulnerability lies in the cryptographic validation routines used by Brocade Fabric OS when processing license keys. The system appears to lack proper signature verification mechanisms or employs weak cryptographic functions that fail to adequately validate the authenticity of license strings. This weakness allows attackers to craft license keys that bypass the normal authentication checks, effectively enabling them to install fraudulent licenses that appear legitimate to the operating system. The flaw operates at the software level within the license management subsystem, where the cryptographic integrity checks are insufficient to detect manipulated or forged license data. This vulnerability aligns with CWE-327, which addresses the use of weak or broken cryptographic algorithms, and represents a failure in proper key validation protocols.
The operational impact of this vulnerability extends beyond simple unauthorized access to premium features, as it fundamentally compromises the security posture of Brocade Fabric OS platforms. An attacker who successfully exploits this vulnerability could gain access to advanced networking capabilities, extended feature sets, and potentially enable malicious activities such as unauthorized network monitoring or traffic manipulation. The ability to forge legitimate license keys also provides attackers with persistent access to systems that might otherwise be restricted to authorized users. This vulnerability creates opportunities for lateral movement within networks, as attackers could use the legitimate license keys to access additional systems or escalate privileges. The implications are particularly severe in enterprise environments where Brocade Fabric OS platforms manage critical network infrastructure and security controls.
Organizations affected by CVE-2021-27795 should implement immediate mitigations including firmware updates from Brocade that address the cryptographic validation weaknesses in the license key system. Network administrators should monitor for unauthorized license key installations and implement strict access controls for license management functions. The vulnerability demonstrates the importance of proper cryptographic implementation and validation, aligning with ATT&CK technique T1556.002 for credential manipulation through license key forgery. Security teams should also consider implementing network segmentation and monitoring to detect unusual license key activity patterns that might indicate exploitation attempts. Regular vulnerability assessments should be conducted to ensure that cryptographic implementations meet industry standards and that proper certificate validation procedures are in place to prevent similar weaknesses from emerging in other system components.