CVE-2019-1845 in Unified Communications Manager IM
Summary
by MITRE
A vulnerability in the authentication service of the Cisco Unified Communications Manager IM and Presence (Unified CM IM&P) Service, Cisco TelePresence Video Communication Server (VCS), and Cisco Expressway Series could allow an unauthenticated, remote attacker to cause a service outage for users attempting to authenticate, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient controls for specific memory operations. An attacker could exploit this vulnerability by sending a malformed Extensible Messaging and Presence Protocol (XMPP) authentication request to an affected system. A successful exploit could allow the attacker to cause an unexpected restart of the authentication service, preventing users from successfully authenticating. Exploitation of this vulnerability does not impact users who were authenticated prior to an attack.
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Analysis
by VulDB Data Team • 09/28/2023
This vulnerability resides within the authentication mechanisms of Cisco's unified communications platforms, specifically affecting the Cisco Unified Communications Manager IM and Presence service, Cisco TelePresence Video Communication Server, and Cisco Expressway Series devices. The flaw represents a critical weakness in the system's memory management protocols that fails to properly validate incoming authentication requests. The vulnerability stems from inadequate input validation and memory operation controls that allow malformed XMPP authentication requests to trigger unexpected system behavior. According to CWE-129, this represents an insufficient input validation issue where the system fails to properly sanitize or validate external inputs before processing them. The attack vector requires remote exploitation without authentication, making it particularly dangerous as any external party can potentially target these systems. The vulnerability operates at the application layer of the network stack, specifically targeting the authentication service components that handle XMPP protocol communications.
The technical exploitation occurs when an attacker crafts a malformed XMPP authentication request that contains maliciously formatted data structures or memory operations that the vulnerable systems cannot properly handle. This malformed input triggers memory corruption or buffer overflow conditions within the authentication service processes, causing the system to unexpectedly restart or crash. The authentication service becomes unavailable for legitimate users attempting to establish connections, creating a denial of service condition that prevents normal communication operations. The system's failure to implement proper memory boundary checks and input sanitization mechanisms allows the attacker to manipulate the service's internal state through carefully constructed protocol messages. The vulnerability does not affect already authenticated sessions, meaning users who have successfully logged in before the attack can continue their operations, but new authentication attempts fail completely. This behavior aligns with ATT&CK technique T1499.004 which describes network disruption attacks that target service availability.
The operational impact of this vulnerability extends beyond simple service disruption as it affects the core communication infrastructure of organizations relying on Cisco unified communications systems. Businesses dependent on these platforms for voice, video, and messaging services face significant operational risks including complete communication outages, productivity losses, and potential security implications from the system instability. The vulnerability affects organizations across multiple industries including healthcare, finance, and government sectors where communication reliability is critical. Organizations may experience cascading effects as communication failures impact business continuity, customer service operations, and internal coordination processes. The attack requires minimal technical expertise to execute, making it accessible to a broad range of threat actors from script kiddies to organized cybercriminals. The fact that exploitation does not require authentication credentials makes it particularly attractive to attackers seeking to disrupt services without detection, as the attack leaves minimal forensic traces in the system logs.
Mitigation strategies should focus on implementing immediate network-level protections through firewalls and access control lists to restrict XMPP traffic to trusted sources only. Cisco has released patches and software updates addressing this vulnerability that should be deployed immediately across all affected systems. Organizations should also implement monitoring solutions to detect unusual authentication service behavior or restart patterns that might indicate exploitation attempts. Network segmentation strategies can help limit the potential impact by isolating critical communication systems from general network access. The implementation of intrusion detection systems capable of identifying malformed XMPP traffic patterns provides an additional layer of protection. Regular security assessments and vulnerability scanning should be conducted to identify other potential weaknesses in the communication infrastructure. Organizations should also review their incident response procedures to ensure rapid detection and remediation of similar vulnerabilities. The fix typically involves strengthening input validation mechanisms and implementing proper memory management controls that prevent malformed data from causing service disruptions. Additionally, implementing redundant authentication services and failover mechanisms can help maintain communication availability during potential exploitation attempts.