CVE-2018-4993 in Acrobat Reader
Summary
by MITRE
Adobe Acrobat and Reader versions 2018.011.20038 and earlier, 2017.011.30079 and earlier, and 2015.006.30417 and earlier have an NTLM SSO hash theft vulnerability. Successful exploitation could lead to information disclosure.
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Analysis
by VulDB Data Team • 04/24/2025
The vulnerability identified as CVE-2018-4993 affects Adobe Acrobat and Reader software across multiple version ranges including 2018.011.20038 and earlier, 2017.011.30079 and earlier, and 2015.006.30417 and earlier. This represents a significant security flaw that resides in the implementation of NTLM Single Sign-On functionality within the affected software versions. The vulnerability specifically targets the authentication mechanisms that allow users to seamlessly access network resources without repeatedly entering credentials, which is a common feature in enterprise environments where Active Directory integration is prevalent.
The technical flaw manifests as an improper handling of NTLM authentication tokens during the Single Sign-On process. When users attempt to access network resources through Adobe Acrobat or Reader, the software fails to properly validate or sanitize the NTLM hash information that is transmitted during authentication. This weakness creates an opportunity for attackers to intercept and potentially steal the NTLM authentication hashes that are typically used to authenticate users within Windows domain environments. The vulnerability is particularly concerning because NTLM hashes are often used as the basis for authentication in corporate networks, making them valuable targets for attackers seeking persistent access to enterprise systems.
From an operational impact perspective, successful exploitation of this vulnerability could result in unauthorized access to sensitive corporate resources and data. An attacker who successfully steals NTLM hashes could potentially use them to authenticate as legitimate users within the network, gaining access to file servers, databases, and other protected resources. The stolen credentials could also be used in pass-the-hash attacks, allowing attackers to move laterally through the network without needing to know the actual passwords. This vulnerability particularly affects organizations that rely heavily on Adobe Acrobat and Reader for document handling, as these applications are frequently used to open and process documents that may contain links to network resources. The impact extends beyond simple information disclosure to potentially enable complete compromise of enterprise network security.
Organizations should implement immediate mitigations to address this vulnerability, including updating to the latest versions of Adobe Acrobat and Reader where the issue has been resolved. The remediation process should also involve network monitoring to detect potential interception of authentication traffic, as well as implementing network segmentation to limit the potential impact of credential theft. Security teams should also consider disabling NTLM authentication where possible and implementing stronger authentication mechanisms such as Kerberos or modern single sign-on solutions. This vulnerability aligns with CWE-200, which covers "Information Exposure," and relates to ATT&CK technique T1075, "Pass the Hash," demonstrating how this weakness can be leveraged to achieve persistent network access. Organizations should also review their patch management processes to ensure timely deployment of security updates and consider implementing additional security controls such as network access control and endpoint detection and response solutions to detect and prevent exploitation attempts.