CVE-2021-1561 in Secure Email and Web Manager
Summary
by MITRE • 08/19/2021
A vulnerability in the spam quarantine feature of Cisco Secure Email and Web Manager, formerly Cisco Security Management Appliance (SMA), could allow an authenticated, remote attacker to gain unauthorized access and modify the spam quarantine settings of another user. This vulnerability exists because access to the spam quarantine feature is not properly restricted. An attacker could exploit this vulnerability by sending malicious requests to an affected system. A successful exploit could allow the attacker to modify another user's spam quarantine settings, possibly disabling security controls or viewing email messages stored on the spam quarantine interfaces.
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Analysis
by VulDB Data Team • 08/21/2021
The vulnerability identified as CVE-2021-1561 resides within the spam quarantine functionality of Cisco Secure Email and Web Manager, formerly known as Cisco Security Management Appliance. This security flaw represents a critical authorization bypass issue that undermines the fundamental security model of the system. The vulnerability stems from insufficient access controls within the spam quarantine interface, creating a pathway for authenticated attackers to manipulate settings belonging to other users within the same system. The affected system operates under the assumption that legitimate users can only access their own quarantine settings, but the improper implementation of access restrictions allows for cross-user privilege escalation.
The technical exploitation of this vulnerability occurs through the manipulation of web requests sent to the affected Cisco appliance. Attackers can craft malicious HTTP requests that target the spam quarantine management endpoints, effectively bypassing the normal user authentication and authorization mechanisms. This type of vulnerability aligns with CWE-285, which addresses improper authorization issues in software systems, and specifically demonstrates weaknesses in access control implementation. The flaw operates at the application layer where user session management and resource access controls fail to properly validate whether the requesting user has legitimate authorization to modify another user's quarantine settings. The system's failure to implement proper session isolation and user context validation creates an environment where privilege escalation becomes possible through simple request manipulation.
From an operational impact perspective, this vulnerability presents a significant threat to email security and data integrity within organizations relying on Cisco Secure Email and Web Manager. An attacker who successfully exploits this vulnerability can disable critical spam protection mechanisms for targeted users, potentially allowing malicious email traffic to bypass security controls and reach user inboxes. The ability to modify quarantine settings also provides unauthorized access to potentially sensitive email content stored within the spam quarantine interfaces, creating data exposure risks. Organizations may experience increased spam volume, potential phishing attacks reaching end users, and compromised email security posture. The vulnerability's remote exploitation capability means that attackers do not need physical access to the network, and the authenticated nature of the attack suggests that compromised credentials from other sources could be leveraged to achieve this privilege escalation.
The mitigation strategies for CVE-2021-1561 primarily focus on implementing proper access controls and authorization mechanisms within the affected system. Cisco has released patches and software updates addressing this vulnerability, which organizations should deploy immediately to remediate the issue. Network administrators should also implement additional monitoring and logging of quarantine management activities to detect unauthorized access attempts. The vulnerability's characteristics align with ATT&CK technique T1078.004, which covers valid accounts with compromised credentials, as attackers could potentially leverage compromised user accounts to exploit this weakness. Organizations should enforce the principle of least privilege for all administrative functions and implement regular security assessments of web application interfaces. Additionally, implementing web application firewalls and input validation controls can help prevent malicious request manipulation attempts. The remediation process should include comprehensive testing to ensure that access controls are properly enforced and that user contexts are correctly isolated within the application's quarantine management interfaces.