CVE-2007-1099 in Dropbear
Summary
by MITRE
dbclient in Dropbear SSH client before 0.49 does not sufficiently warn the user when it detects a hostkey mismatch, which might allow remote attackers to conduct man-in-the-middle attacks.
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Analysis
by VulDB Data Team • 12/13/2018
The vulnerability identified as CVE-2007-1099 affects the Dropbear SSH client version 0.49 and earlier, presenting a significant security risk through inadequate host key validation mechanisms. This flaw resides in the dbclient component of the Dropbear SSH implementation, which is a lightweight SSH server and client solution designed for embedded systems and environments with limited resources. The vulnerability specifically targets the user warning system that should alert operators when connecting to hosts with mismatched SSH host keys, creating a window of opportunity for malicious actors to exploit the trust relationship between SSH clients and servers.
The technical nature of this vulnerability stems from insufficient validation and warning mechanisms within the SSH client's host key verification process. When a host key mismatch occurs during SSH connection establishment, the Dropbear client fails to provide adequate warning to the user about the potential security threat. This inadequate warning system allows attackers to perform man-in-the-middle attacks by presenting a forged host key to the client, while the user remains unaware of the compromise. The vulnerability directly relates to CWE-310, which addresses cryptographic issues, and more specifically to CWE-312, which deals with cleartext storage of sensitive information, as the failure to warn users about host key mismatches effectively allows attackers to bypass the fundamental security mechanism of SSH host key verification.
The operational impact of this vulnerability extends beyond simple network communication risks to encompass broader security implications for systems relying on SSH for remote access and management. Attackers can exploit this weakness by intercepting SSH connections between legitimate users and servers, potentially gaining unauthorized access to sensitive systems without detection. This vulnerability particularly affects environments where Dropbear SSH clients are used in embedded devices, network appliances, or any system where SSH is employed for secure remote access. The man-in-the-middle attack capability allows for session hijacking, data interception, and potential privilege escalation attacks that could compromise entire network infrastructures. Organizations using Dropbear SSH clients in production environments face significant risk of unauthorized access and data breaches when this vulnerability remains unpatched.
Mitigation strategies for CVE-2007-1099 primarily involve immediate upgrading to Dropbear SSH client version 0.49 or later, which contains the necessary fixes to properly warn users about host key mismatches. System administrators should also implement additional security measures including strict SSH configuration settings, regular host key verification processes, and monitoring for unauthorized SSH connection attempts. The remediation approach aligns with ATT&CK technique T1566, which covers social engineering attacks through man-in-the-middle techniques, as organizations must address both the technical vulnerability and the potential social engineering aspects of host key deception. Network security teams should also consider implementing SSH key management best practices, including regular key rotation, proper key storage procedures, and enhanced logging of SSH connection events to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of proper cryptographic protocol implementation and user awareness in maintaining secure network communications.