CVE-2019-16928 is a critical vulnerability affecting Exim Internet Mailer versions 4.92 through 4.92.2. This vulnerability allows remote code execution through a heap-based buffer overflow in the string_vformat function within string.c, specifically triggered by a long EHLO command. The CVSS score assigned to this vulnerability is 9.8, categorizing it as critical, which signifies its severity and the potential impact on affected systems.
Risk to organizations includes unauthorized access, data breaches, and loss of system integrity. Given the nature of this vulnerability, it is crucial for organizations utilizing the affected versions of Exim to assess their exposure and prioritize immediate action. The urgency for defenders to patch this vulnerability cannot be overstated, as attackers may leverage this flaw to gain control of systems.
As of now, there is no public exploit available, but the presence of this vulnerability in the Known Exploited Vulnerabilities (KEV) catalog underscores its critical nature. Organizations should act swiftly to mitigate risks associated with this vulnerability by applying the necessary updates and configurations as advised by the vendor.
Organizations should prioritize patching immediately. The potential for significant exploitation exists, and timely remediation is essential to safeguard infrastructure.
Vulnerability Details
The official description of CVE-2019-16928 states that it allows remote code execution due to a heap-based buffer overflow in the Exim Internet Mailer. This vulnerability is classified under CWE-787, indicating a flaw related to improper control of a resource through its lifetime.
The CVSS score of 9.8 signifies a critical severity level, indicating a high risk for confidentiality, integrity, and availability impacts. Affected products include Exim versions from 4.92 through 4.92.2, and the vulnerability was published on September 27, 2019.
Technical Analysis
The root cause of CVE-2019-16928 is a heap-based buffer overflow that occurs when the Exim Internet Mailer processes a long EHLO command. This vulnerability can be exploited through a network attack vector, requiring no privileges or user interaction, making it particularly dangerous.
The attack complexity is low, meaning that an attacker could exploit this vulnerability with minimal effort. Given that the vulnerability impacts confidentiality, integrity, and availability, the potential for severe damage is high.
Risk & Impact Analysis
Real-world deployment of the Exim Internet Mailer with this vulnerability poses significant risks. Organizations leveraging affected versions are at high risk of remote code execution, potentially leading to unauthorized system access and data breaches.
The urgency of addressing this vulnerability is underscored by its CVSS score of 9.8 and the existence of its entry in the KEV catalog. Organizations must assess their exposure and prioritize remediation in their patch management processes.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | Yes |
Ransomware Use | No |
Affected Versions
Affected versions include Exim from 4.92 to 4.92.2, as well as various Linux distributions such as Ubuntu 19.04 and Debian 10.0. Organizations running these versions should take immediate action to update their systems.
Mitigation & Remediation
To mitigate the risks associated with CVE-2019-16928, organizations should apply the available patches provided by the vendor. It is recommended to upgrade to versions of Exim that do not contain this vulnerability. If immediate patching is not possible, organizations may implement network controls to limit exposure to untrusted networks.
For more information on best practices for security testing, organizations should consider reviewing our guide on penetration testing strategies.
Detection Guidance
Organizations should monitor logs for unusual behaviors indicative of exploitation, such as unexpected EHLO command lengths or unusual network traffic patterns. Behavioral anomalies can be key indicators of attempts to exploit this vulnerability.
AppSecure Threat Intelligence Insight
CVE-2019-16928 represents a significant threat to organizations that rely on Exim for their email services. The presence of this vulnerability in the KEV catalog highlights the urgency for organizations to prioritize its remediation. Security teams should learn from this incident to improve their monitoring and patching strategies.
For further reading on vulnerability management, organizations can explore our article on designing a vulnerability management program and how to effectively address emerging threats.
Additionally, organizations should review our insights on penetration testing methodology to strengthen their defenses against similar vulnerabilities.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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