CVE-2023-1786 in cloud-init
Summary
by MITRE • 04/27/2023
Sensitive data could be exposed in logs of cloud-init before version 23.1.2. An attacker could use this information to find hashed passwords and possibly escalate their privilege.
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Analysis
by VulDB Data Team • 10/17/2025
The vulnerability identified as CVE-2023-1786 represents a critical logging security flaw within the cloud-init framework that affects versions prior to 23.1.2. Cloud-init serves as a crucial initialization utility for cloud instances, handling various configuration tasks during system boot processes including user data processing and system setup. This vulnerability specifically targets the logging mechanisms employed by cloud-init, creating an unintended information disclosure channel that could significantly compromise system security. The flaw arises from improper handling of sensitive data within log output, where hashed passwords and potentially other credential information may be inadvertently written to system logs, making them accessible to unauthorized users or processes with log access privileges.
The technical implementation of this vulnerability stems from inadequate sanitization of sensitive data during logging operations within the cloud-init codebase. When cloud-init processes user data or configuration information containing hashed passwords, the system fails to properly filter or redact this sensitive information before writing entries to log files. This creates a scenario where attackers with access to system logs can extract hashed password values and potentially leverage this information for privilege escalation attacks. The vulnerability manifests as a direct consequence of insufficient input validation and output sanitization within the logging subsystem, allowing sensitive credential information to persist in plaintext or obfuscated formats within log files accessible to local users or processes.
The operational impact of CVE-2023-1786 extends beyond simple information disclosure, creating potential pathways for privilege escalation and lateral movement within cloud environments. Attackers who gain access to system logs can extract hashed passwords and use them as part of broader attack vectors including password cracking attempts, credential reuse attacks, or as stepping stones for more sophisticated exploitation techniques. This vulnerability particularly affects cloud deployments where multiple users share the same infrastructure or where log files are not properly secured, creating opportunities for unauthorized access to sensitive authentication information. The exposure of hashed passwords in logs provides attackers with valuable intelligence for offline password cracking operations, potentially leading to full system compromise.
Security professionals should implement immediate mitigation strategies including updating cloud-init to version 23.1.2 or later, which contains the necessary patches to address the logging sanitization issues. System administrators must also conduct comprehensive log file reviews to identify and remove any previously exposed sensitive information, while implementing proper log access controls and monitoring procedures. The vulnerability aligns with CWE-200, which addresses "Information Exposure," and relates to ATT&CK technique T1565.001 for "Data Manipulation: Stored Data Manipulation," as it creates opportunities for attackers to access and potentially manipulate stored credential information. Organizations should also consider implementing additional security controls such as log file encryption, access restriction policies, and regular security auditing of log content to prevent similar vulnerabilities from being exploited in the future.