CVE-2020-15829 in TeamCity
Summary
by MITRE
In JetBrains TeamCity before 2019.2.3, password parameters could be disclosed via build logs.
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Analysis
by VulDB Data Team • 08/09/2020
This vulnerability affects JetBrains TeamCity versions prior to 2019.2.3 and represents a critical information disclosure flaw that compromises the security of sensitive authentication data. The vulnerability stems from improper handling of password parameters within the build logging mechanism, where credentials specified as build parameters are inadvertently exposed in plaintext within the build output logs. This occurs when administrators configure build steps that utilize password parameters, which are then processed and displayed in the console output without adequate sanitization or obfuscation measures. The flaw directly violates fundamental security principles regarding credential handling and logging practices, creating a significant risk for organizations that rely on TeamCity for continuous integration and deployment processes.
The technical implementation of this vulnerability involves the build system's parameter substitution mechanism where password values are replaced into build scripts and command executions without proper masking or filtering. When build processes execute commands that include password parameters, these values appear in the build logs in clear text format, making them accessible to anyone with access to the build output or log files. This issue is particularly dangerous because it occurs at the logging level rather than during the actual credential transmission or storage phases, meaning that even properly secured credential storage mechanisms can be undermined by this logging behavior. The vulnerability aligns with CWE-200 which addresses "Information Exposure" and specifically relates to improper logging of sensitive information, as well as CWE-522 which deals with "Insufficiently Protected Credentials" in the context of logging operations.
The operational impact of CVE-2020-15829 extends beyond immediate credential exposure to encompass broader security implications for development environments and deployment pipelines. Organizations using affected TeamCity versions face potential compromise of their entire CI/CD infrastructure when build logs containing passwords are accessible to unauthorized users, including those with read access to build servers, log repositories, or even external systems that might aggregate these logs. The vulnerability affects not just individual password parameters but any sensitive information that might be passed through build parameters, potentially exposing API keys, database credentials, and other authentication tokens. This creates a persistent risk where compromised credentials can be used for unauthorized access to development environments, production systems, and associated services, with potential lateral movement opportunities within the network infrastructure.
Mitigation strategies for this vulnerability primarily involve upgrading to JetBrains TeamCity version 2019.2.3 or later, which includes proper parameter sanitization and logging controls. Organizations should implement comprehensive log review procedures to identify and remove any existing compromised credentials from build logs, while also establishing logging policies that prevent sensitive parameter values from appearing in output streams. Additional protective measures include configuring parameter masking in build configurations, implementing access controls to build log repositories, and conducting regular security audits of CI/CD environments. From a defensive perspective, this vulnerability demonstrates the importance of following the principle of least privilege in logging systems and aligns with ATT&CK technique T1552.001 which addresses "Credentials In Files" and T1078.004 which covers "Valid Accounts: Cloud Accounts" in the context of protecting sensitive information within automated build processes. Organizations should also consider implementing automated monitoring solutions that can detect and alert on the presence of credential-like patterns in build outputs, as well as establish incident response procedures for credential compromise scenarios involving CI/CD systems.