Arch Linux pacman Remote Installation Directory Traversal Vulnerability [CVE-2019-9686]
CVE Number – CVE-2019-9686
A vulnerability in pacman could allow an unauthenticated, remote attacker to excute arbitrary code on a targeted system.
The vulnerability exists in the curl_download_internal function, as defined in the lib/libalpm/dload.csource code file of the affected software, and is due to improper validation of user-supplied input when remote package installation operations are performed. An attacker with control of the remote package server, or with sufficient network access to perform a man-in-the-middle attack, could exploit this vulnerability by sending a Content-Disposition header that submits malicious input to the affected software when a user executes the pacman -U url command. A successful exploit could allow the attacker to place a file with malicious content on the users system that could execute arbitrary code with root privileges and completely compromise the system.
Arch Linux has confirmed the vulnerability and released software updates.
Analysis
- To exploit this vulnerability, the attacker must send malicious requests to the targeted system, making exploitation more difficult in environments that restrict network access from untrusted sources.
Safeguards
- Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators are advised to run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators can help protect affected systems from external attacks by using a solid firewall strategy.
Administrators are advised to monitor affected systems.
Vendor Announcements
- Arch Linux has published a security advisory for CVE-2019-9686 at the following link: [ASA-201903-7] pacman: arbitrary code execution
Fixed Software
- Arch Linux has released source code and software updates at the following links: Sanitize file name received from Content-Disposition header and pacman
Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.