CVE-2017-8825 in LibEtPan
Summary
by MITRE
A null dereference vulnerability has been found in the MIME handling component of LibEtPan before 1.8, as used in MailCore and MailCore 2. A crash can occur in low-level/imf/mailimf.c during a failed parse of a Cc header containing multiple e-mail addresses.
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Analysis
by VulDB Data Team • 12/06/2022
The null dereference vulnerability identified as CVE-2017-8825 represents a critical flaw within the MIME handling capabilities of LibEtPan library versions prior to 1.8. This vulnerability specifically affects applications that rely on MailCore and MailCore 2 implementations, creating potential points of system instability and service disruption. The issue manifests within the low-level parsing functions of the library, particularly in the mailimf.c file where the internal structure for handling email headers is processed. The vulnerability stems from inadequate input validation and error handling mechanisms that fail to properly manage malformed email header data during the parsing process. When a Cc header contains multiple email addresses in a format that triggers parsing failure, the library attempts to dereference a null pointer, leading to immediate system termination or application crash.
The technical implementation of this vulnerability resides in the mailimf.c module where the parsing logic does not adequately check for null pointer conditions before attempting to access memory locations. This represents a classic null pointer dereference issue that falls under CWE-476, which specifically addresses the use of null pointers in software implementations. The flaw occurs during the processing of email headers where the library expects certain data structures to be properly initialized but encounters null values instead. The parsing of Cc headers with multiple addresses creates a scenario where the internal state management fails to account for edge cases in header formatting, particularly when addresses are improperly formatted or contain unexpected delimiters. This vulnerability demonstrates poor defensive programming practices where error conditions are not properly handled, leading to abrupt program termination.
The operational impact of CVE-2017-8825 extends beyond simple application crashes to potentially disrupt email services and communication systems that depend on affected libraries. When exploited, this vulnerability can cause denial of service conditions where legitimate email processing fails, affecting both individual users and enterprise email infrastructure. The vulnerability is particularly concerning in environments where automated email processing systems are deployed, as these systems may become unstable and require manual intervention to restore service. Security researchers have noted that this type of vulnerability can be exploited by malicious actors to perform service disruption attacks, making it a significant concern for email server administrators and security teams. The low-level nature of the flaw means that it can potentially be leveraged in more sophisticated attack scenarios, though direct exploitation for code execution appears limited based on the nature of the null pointer dereference.
Mitigation strategies for CVE-2017-8825 focus primarily on upgrading affected software components to LibEtPan version 1.8 or later, where the null pointer dereference has been addressed through improved input validation and error handling mechanisms. System administrators should prioritize patching affected MailCore and MailCore 2 implementations to prevent exploitation and maintain service availability. Additionally, implementing proper input sanitization at the application level can provide additional defense in depth, though this approach is less reliable than addressing the root cause in the library itself. Network monitoring solutions should be configured to detect unusual email processing failures that might indicate exploitation attempts. Organizations should also consider implementing email filtering and validation mechanisms that can identify and quarantine malformed email headers before they reach vulnerable applications. The vulnerability aligns with ATT&CK technique T1499.004 which covers network denial of service attacks, making it a relevant consideration for incident response planning and security posture assessments.