CVE-2007-2188 in eXtremail
Summary
by MITRE
eXtremail 2.1.1 and earlier does not verify the ID field (aka transaction id) in DNS responses, which makes it easier for remote attackers to conduct DNS spoofing.
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Analysis
by VulDB Data Team • 08/29/2018
The vulnerability identified as CVE-2007-2188 affects eXtremail versions 2.1.1 and earlier, specifically targeting the DNS resolution mechanism within the email server software. This flaw resides in the protocol handling logic where the application fails to properly validate the ID field in DNS responses, creating a significant security weakness that can be exploited by malicious actors. The issue represents a fundamental failure in the DNS transaction integrity verification process, which is critical for maintaining the trustworthiness of network communications. The vulnerability allows attackers to manipulate DNS responses without proper authentication or verification, undermining the core security assumptions of the Domain Name System.
The technical flaw manifests in the improper handling of DNS transaction identifiers, where eXtremail does not validate that the ID field in incoming DNS responses matches the ID field of the original DNS query sent by the application. This omission creates a window of opportunity for attackers to intercept DNS queries and respond with forged DNS records that appear legitimate to the vulnerable application. The ID field serves as a critical mechanism for correlating DNS requests and responses, and its absence of validation allows for successful DNS spoofing attacks. This vulnerability directly relates to CWE-209, which describes improper handling of DNS transaction identifiers, and can be classified under the broader category of DNS cache poisoning attacks. The flaw essentially removes a crucial security check that should prevent malicious responses from being accepted as legitimate.
The operational impact of this vulnerability extends beyond simple DNS spoofing, as it can enable more sophisticated attacks including man-in-the-middle operations, email redirection, and potential data interception. Remote attackers can exploit this weakness to redirect email traffic to malicious servers, compromise email authentication mechanisms, or gain unauthorized access to email services. The vulnerability affects the integrity of DNS resolution within the eXtremail environment, potentially allowing attackers to manipulate email routing decisions and compromise the confidentiality and availability of email communications. This weakness can be particularly damaging in enterprise environments where email systems serve as critical communication infrastructure, and the ability to manipulate DNS responses can lead to widespread service disruption and data compromise.
Mitigation strategies for CVE-2007-2188 should focus on immediate patching of the eXtremail software to versions that properly validate DNS transaction identifiers. Organizations should implement additional network security controls including DNS security extensions, DNS query response validation, and monitoring for anomalous DNS traffic patterns. The implementation of DNSSEC (Domain Name System Security Extensions) can provide additional layers of protection against this type of attack by ensuring the authenticity and integrity of DNS responses. Network segmentation and access controls should be enhanced to limit the impact of potential DNS spoofing attempts, while regular security audits should verify that DNS transaction validation mechanisms are properly functioning. This vulnerability aligns with ATT&CK technique T1071.004, which describes DNS tunneling and manipulation, and represents a classic example of how insufficient input validation in network protocols can lead to critical security breaches. Organizations should also consider implementing intrusion detection systems that can identify and alert on suspicious DNS response patterns that may indicate exploitation attempts.