CVE-2017-7501 in RPM
Summary
by MITRE
It was found that versions of rpm before 4.13.0.2 use temporary files with predictable names when installing an RPM. An attacker with ability to write in a directory where files will be installed could create symbolic links to an arbitrary location and modify content, and possibly permissions to arbitrary files, which could be used for denial of service or possibly privilege escalation.
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Analysis
by VulDB Data Team • 01/11/2023
The vulnerability identified as CVE-2017-7501 represents a critical security flaw in the rpm package management system affecting versions prior to 4.13.0.2. This issue stems from the predictable naming convention used for temporary files during RPM installation processes, creating opportunities for malicious exploitation. The vulnerability specifically impacts systems where rpm is used for package management, particularly in enterprise environments where package installation and updates are frequent operations.
The technical flaw manifests when rpm creates temporary files during package installation with predictable names that do not incorporate sufficient randomness or unique identifiers. This predictable naming scheme allows attackers who have write access to directories where package files will be installed to create symbolic links that point to sensitive system files or directories. When rpm attempts to write to these predictable temporary file locations, it inadvertently modifies the target files pointed to by the symbolic links, potentially allowing unauthorized modification of critical system components.
From an operational perspective, this vulnerability presents significant risks including potential privilege escalation and denial of service conditions. An attacker with limited write permissions in installation directories could exploit this flaw to modify system files with elevated privileges, potentially compromising the integrity of the entire system. The impact extends beyond simple file modification, as attackers could manipulate permissions or create malicious files that execute with higher privileges than intended, particularly when the rpm installation process runs with elevated privileges.
The vulnerability aligns with CWE-377, which addresses insecure temporary file handling, and relates to ATT&CK technique T1068, which covers privilege escalation through exploitation of software vulnerabilities. Organizations using rpm package management systems are particularly at risk, as this flaw can be exploited in various scenarios including compromised user accounts, insider threats, or environments where users have write access to installation directories. The attack vector is particularly concerning in multi-user systems where file permissions are not strictly enforced.
Mitigation strategies include immediate upgrading to rpm version 4.13.0.2 or later, which implements proper randomization of temporary file names during package installation. System administrators should also implement strict directory permissions and monitoring of installation directories to prevent unauthorized write access. Additional protective measures include implementing file integrity monitoring solutions and ensuring that package installation processes run with minimal required privileges. Organizations should conduct vulnerability assessments to identify systems running vulnerable rpm versions and establish automated patch management processes to prevent similar issues in the future.