CVE-2007-1820 in Meridian Mail
Summary
by MITRE
Nortel Networks CallPilot and Meridian Mail voicemail systems, when a mailbox has auto logon enabled, allow remote attackers to retrieve or remove messages, or reconfigure the mailbox, by spoofing Calling Number Identification (CNID, aka Caller ID).
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Analysis
by VulDB Data Team • 07/23/2024
The vulnerability described in CVE-2007-1820 represents a critical security flaw in Nortel Networks CallPilot and Meridian Mail voicemail systems that exploits the trust relationship between the system and caller identification data. This weakness specifically manifests when auto logon functionality is enabled on voicemail mailboxes, creating an attack vector that allows remote adversaries to manipulate voicemail contents without proper authentication. The vulnerability stems from the system's failure to properly validate the authenticity of Calling Number Identification (CNID) information, which is typically used to identify incoming calls and establish caller context within telephony systems. When attackers spoof CNID data, they can trick the voicemail system into treating their malicious calls as legitimate, thereby gaining unauthorized access to sensitive voicemail content and mailbox configurations.
The technical implementation of this vulnerability relies on the fundamental assumption that CNID information presented by calling parties can be trusted without verification. In normal operation, voicemail systems use CNID to establish caller identity and potentially trigger auto logon features for known users. However, this vulnerability demonstrates that the systems lack proper authentication mechanisms to validate the source of CNID data, allowing attackers to craft and send spoofed calling number information. The attack process involves an adversary sending a specially crafted call with falsified CNID data that matches an existing mailbox or user account, thereby triggering the auto logon functionality and granting access to the target mailbox. This design flaw directly violates security principles of input validation and authentication, as outlined in CWE-284 for improper access control and CWE-20 for improper input validation.
The operational impact of this vulnerability extends beyond simple unauthorized access to voicemail content, encompassing complete mailbox compromise and potential information disclosure. Attackers can retrieve sensitive voice messages that may contain confidential business information, personal data, or proprietary communications, creating significant privacy and security risks for organizations using these systems. The ability to remove messages allows for destruction of evidence and potential disruption of business communications, while the mailbox reconfiguration capability enables persistent access and potential data manipulation. This vulnerability affects organizations that rely on traditional telephony systems for business communication, particularly those with auto logon features enabled, creating a significant risk for companies that handle sensitive information or operate in regulated environments where communication privacy is paramount.
Mitigation strategies for this vulnerability must address both the immediate security gap in CNID validation and the broader architectural issues that allow such spoofing attacks. Organizations should disable auto logon functionality on voicemail systems when possible, implement additional authentication layers beyond CNID, and establish proper input validation mechanisms for all caller identification data. Network-level protections such as call authentication protocols and CNID verification systems should be deployed to prevent spoofing attacks. The vulnerability also highlights the importance of implementing defense-in-depth strategies and adhering to security frameworks such as those outlined in the ATT&CK matrix for network intrusion detection, particularly focusing on credential access and privilege escalation techniques. System administrators should also consider implementing monitoring and alerting mechanisms to detect unusual patterns of mailbox access that may indicate exploitation attempts, ensuring compliance with industry standards for telephony security and information protection.