CVE-2017-11397 in Encryption for Email
Summary
by MITRE
A service DLL preloading vulnerability in Trend Micro Encryption for Email versions 5.6 and below could allow an unauthenticated remote attacker to execute arbitrary code on a vulnerable system.
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Analysis
by VulDB Data Team • 12/15/2019
The vulnerability identified as CVE-2017-11397 represents a critical service DLL preloading flaw affecting Trend Micro Encryption for Email versions 5.6 and earlier. This vulnerability stems from improper handling of dynamic link library loading sequences within the email encryption service, creating an exploitable condition where malicious code can be executed with elevated privileges. The flaw specifically manifests when the system attempts to load a required DLL component, allowing an attacker to manipulate the loading process through crafted file placement in strategic directories.
This vulnerability operates under the broader category of DLL preloading attacks, which fall under CWE-426 - Untrusted Search Path, and aligns with ATT&CK technique T1068 - Exploitation for Privilege Escalation. The attack vector is particularly dangerous as it enables unauthenticated remote code execution, meaning that an attacker does not require valid credentials to exploit the vulnerability. The service DLL preloading mechanism in Trend Micro Encryption for Email fails to properly validate the path from which DLLs are loaded, creating a window of opportunity where attacker-controlled DLLs can be loaded in place of legitimate system components. This behavior violates fundamental security principles of secure coding practices and proper DLL loading mechanisms.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a potential pathway to establish persistent access within email environments. When exploited successfully, the vulnerability allows attackers to execute arbitrary code with the privileges of the running service, which typically operates with elevated permissions. This creates significant risk for organizations using affected versions of Trend Micro Encryption for Email, as the compromised system could be used to intercept encrypted communications, exfiltrate sensitive data, or serve as a foothold for further network infiltration. The vulnerability affects the email encryption service itself, potentially compromising the security of encrypted email communications that organizations rely upon for protecting sensitive information.
Organizations should immediately implement mitigations including updating to Trend Micro Encryption for Email version 5.7 or later, which contains patches addressing this vulnerability. System administrators should also conduct thorough vulnerability assessments to identify any systems running affected versions and implement network segmentation to limit potential attack surface. The mitigation strategy should include monitoring for suspicious file creation in system directories and implementing strict access controls for email service components. Additionally, organizations should consider deploying application whitelisting solutions to prevent unauthorized DLL execution and ensure that only trusted components can be loaded by the email encryption service. Compliance with security standards such as those outlined in NIST SP 800-128 and ISO 27001 should be maintained throughout the remediation process to ensure comprehensive protection against similar vulnerabilities.