Description Preview
A privilege escalation vulnerability in Ubuntu's implementation of overlayfs allows unprivileged users to set privileged extended attributes on mounted files, bypassing security checks. This vulnerability affects Ubuntu kernels carrying both commit c914c0e27eb0 and the patch "UBUNTU: SAUCE: overlayfs: Skip permission checking for trusted.overlayfs.* xattrs", enabling attackers to gain root privileges.
Overview
CVE-2023-2640 is a serious security vulnerability in Ubuntu's Linux kernel implementation of overlayfs. The issue stems from improper authorization controls (CWE-863) that allow unprivileged users to set privileged extended attributes on files. When these attributes are set on mounted files, they propagate to the upper files without undergoing the appropriate security checks. This vulnerability can be exploited by local users to escalate privileges to root, effectively compromising the entire system. The vulnerability was discovered by security researchers at Wiz.io and has been dubbed "OverlayFS Unpriv" as part of a pair of vulnerabilities affecting Ubuntu systems.
Remediation
To remediate this vulnerability, system administrators should:
- Update affected Ubuntu systems immediately with the security patches provided in USN-6250-1.
- Apply all available kernel updates through standard Ubuntu update mechanisms:
- Run
sudo apt update && sudo apt upgradeto install the latest security patches - Reboot the system after updates are installed to ensure the patched kernel is in use
- Run
For systems that cannot be immediately patched:
- Consider implementing additional access controls to limit who can access the affected systems
- Monitor system logs for suspicious activities that might indicate exploitation attempts
- Consider isolating affected systems from sensitive networks until patching is possible
References
- Ubuntu Security Notice USN-6250-1: https://ubuntu.com/security/notices/USN-6250-1
- Wiz.io Technical Analysis: https://wiz.io/blog/ubuntu-overlayfs-vulnerability
- Ubuntu Kernel Team Patch: https://lists.ubuntu.com/archives/kernel-team/2023-July/140923.html
- MITRE CVE Entry: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-2640
Industry ExposureMost to leastThis section illustrates the prevalence of a specific Common Vulnerabilities and Exposures (CVE) across various industries based on customer reports. The ranking displays industries from the most to least affected by this particular vulnerability, offering valuable insight into where this CVE has been most frequently observed. This information can help organizations within these sectors prioritize their security efforts, understand their relative risk exposure compared to their peers, and focus remediation strategies where they are most needed. By understanding the industry-specific impact, organizations can make more informed decisions regarding patching, resource allocation, and overall risk management related to this CVE.
This section illustrates the prevalence of a specific Common Vulnerabilities and Exposures (CVE) across various industries based on customer reports. The ranking displays industries from the most to least affected by this particular vulnerability, offering valuable insight into where this CVE has been most frequently observed. This information can help organizations within these sectors prioritize their security efforts, understand their relative risk exposure compared to their peers, and focus remediation strategies where they are most needed. By understanding the industry-specific impact, organizations can make more informed decisions regarding patching, resource allocation, and overall risk management related to this CVE.
- ManufacturingManufacturing
- Finance and InsuranceFinance and Insurance
- InformationInformation
- Other Services (except Public Administration)Other Services (except Public Administration)
- Public AdministrationPublic Administration
- Arts, Entertainment & RecreationArts, Entertainment & Recreation
- Educational ServicesEducational Services
- Health Care & Social AssistanceHealth Care & Social Assistance
- Professional, Scientific, & Technical ServicesProfessional, Scientific, & Technical Services
- Wholesale TradeWholesale Trade
- Accommodation & Food ServicesAccommodation & Food Services
- Administrative, Support, Waste Management & Remediation ServicesAdministrative, Support, Waste Management & Remediation Services
- Agriculture, Forestry Fishing & HuntingAgriculture, Forestry Fishing & Hunting
- ConstructionConstruction
- Management of Companies & EnterprisesManagement of Companies & Enterprises
- MiningMining
- Real Estate Rental & LeasingReal Estate Rental & Leasing
- Retail TradeRetail Trade
- Transportation & WarehousingTransportation & Warehousing
- UtilitiesUtilities
