CVE-2017-9271 in zypper
Summary
by MITRE
The commandline package update tool zypper writes HTTP proxy credentials into its logfile, allowing local attackers to gain access to proxies used.
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Analysis
by VulDB Data Team • 02/16/2023
The vulnerability identified as CVE-2017-9271 affects the zypper package management tool used in openSUSE and SUSE Linux Enterprise systems. This issue represents a critical security flaw in how the tool handles proxy authentication credentials during package updates. The vulnerability stems from zypper's improper handling of HTTP proxy credentials, specifically its tendency to log these sensitive authentication details in plain text within its operational logs. This behavior creates an exploitable condition where local attackers with access to system logs can extract proxy credentials and potentially use them to gain unauthorized access to corporate networks or bypass security controls.
The technical implementation of this vulnerability occurs when zypper processes package update commands that require proxy authentication. During the authentication process, the tool includes the proxy username and password in its logging mechanism, typically writing these credentials to log files that may be accessible to local users. The flaw exists in the logging subsystem where zypper fails to sanitize proxy authentication parameters before writing them to log files, creating a clear text exposure of sensitive network credentials. This issue is particularly concerning because it affects the core package management functionality that system administrators rely on for maintaining system security and updates, making it a high-impact vulnerability in enterprise environments where proxy servers are commonly used for network access control.
From an operational perspective, this vulnerability creates significant risk for organizations using SUSE-based systems that employ proxy servers for internet access. Local attackers with basic user privileges can exploit this flaw to extract proxy credentials from log files, potentially gaining access to corporate networks, internal resources, or bypassing security controls that rely on proxy authentication. The impact extends beyond simple credential theft, as attackers could use these credentials to perform unauthorized package installations, access restricted network resources, or establish persistent access to the network infrastructure. This vulnerability directly violates security principles of least privilege and proper credential handling, as it demonstrates a failure in secure logging practices and sensitive data protection mechanisms.
The security implications of CVE-2017-9271 align with CWE-532, which addresses information exposure through log files, and relates to ATT&CK technique T1078 for valid accounts and T1566 for credential access through exploitation of local system vulnerabilities. Organizations should implement immediate mitigations including restricting access to zypper log files, implementing proper log sanitization for proxy credentials, and ensuring that system administrators regularly audit log file permissions. The recommended remediation involves updating to patched versions of zypper where proxy credentials are no longer logged in plain text, implementing proper log rotation and access controls, and establishing monitoring for unauthorized access to system logs. Additionally, organizations should consider implementing network segmentation and credential management solutions to reduce the potential impact of credential exposure, as this vulnerability demonstrates the importance of secure handling of authentication data in system management tools.