CVE-2016-1423 in Email Security Appliance
Summary
by MITRE
A vulnerability in the display of email messages in the Messages in Quarantine (MIQ) view in Cisco AsyncOS for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause a user to click a malicious link in the MIQ view. The malicious link could be used to facilitate a cross-site scripting (XSS) or HTML injection attack. More Information: CSCuz02235. Known Affected Releases: 8.0.2-069. Known Fixed Releases: 9.1.1-038 9.7.2-047.
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Analysis
by VulDB Data Team • 10/14/2024
The vulnerability identified as CVE-2016-1423 resides within the Cisco AsyncOS email security appliance platform, specifically affecting the Messages in Quarantine (MIQ) view functionality. This security flaw represents a critical concern for organizations relying on Cisco Email Security Appliance for email protection, as it enables unauthenticated remote attackers to manipulate the display of quarantined email messages. The vulnerability stems from insufficient input validation and output encoding within the MIQ interface, creating a pathway for malicious actors to inject harmful content that appears legitimate to end users. The affected version 8.0.2-069 demonstrates how legacy systems often contain inherent weaknesses that persist across multiple releases, requiring careful attention to patch management and system updates.
The technical execution of this vulnerability occurs through cross-site scripting attacks that exploit the improper handling of user-supplied data within the MIQ view display mechanism. When a user accesses the quarantine interface, the system fails to adequately sanitize or encode potentially malicious content that may be present in quarantined email headers or body content. This allows an attacker to craft specially formatted email messages that, when displayed in the MIQ view, execute malicious JavaScript code or HTML injection payloads. The attack vector leverages the trust relationship between the user and the email security interface, as users expect to see legitimate quarantined messages without security concerns. The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and demonstrates how improper input validation can lead to unauthorized code execution in web applications. The attack scenario typically involves an attacker sending a malicious email with crafted headers or content that, when processed by the ESA system, becomes embedded in the MIQ display and subsequently executed when users interact with the quarantined message.
The operational impact of CVE-2016-1423 extends beyond simple data theft or system compromise, as it enables sophisticated social engineering attacks that can facilitate broader security breaches. When users encounter malicious links within what appears to be legitimate quarantine notifications, they may inadvertently execute payloads that could lead to credential theft, system compromise, or further network infiltration. The vulnerability creates a persistent threat vector that remains active as long as affected systems remain operational, potentially allowing attackers to establish persistent access to email environments. Organizations utilizing the affected Cisco ESA versions face significant risk of phishing campaigns, credential harvesting, and potential lateral movement within their networks. The attack could result in unauthorized access to sensitive corporate communications, data exfiltration, and disruption of email services. This vulnerability directly impacts the CIA triad by potentially compromising confidentiality through data access, integrity through malicious code injection, and availability through service disruption or compromise. The implications for enterprise security are particularly severe given that email remains a primary attack vector in most cyber incidents, and the compromise of email security appliances represents a fundamental breach in organizational defenses.
Mitigation strategies for CVE-2016-1423 require immediate implementation of the vendor-provided patches, specifically targeting the fixed releases 9.1.1-038 and 9.7.2-047, which contain the necessary security updates to address the XSS vulnerability. Organizations should conduct comprehensive vulnerability assessments to identify all affected Cisco ESA appliances and prioritize patch deployment across their email infrastructure. Network segmentation and access controls should be implemented to limit exposure of affected systems, while monitoring for suspicious email patterns or user behavior that might indicate exploitation attempts. Security teams should also implement enhanced email filtering rules and content inspection to detect and block potentially malicious payloads that attempt to exploit similar vulnerabilities. The remediation process must include thorough testing of patches in non-production environments to ensure compatibility with existing email security policies and configurations. Additionally, organizations should conduct user awareness training to educate staff about recognizing suspicious email content and the potential risks associated with clicking links in quarantined messages, as this vulnerability demonstrates how social engineering can compound technical security flaws. Implementation of web application firewalls and additional content filtering layers can provide defense-in-depth against similar exploitation attempts, while regular security audits should verify that all email security components remain properly updated and configured according to best practices.