New Linux Privilege Escalation Flaw Uncovered in Snap Package Manager

Multiple security vulnerabilities have been disclosed in Canonical’s Snap computer software packaging and deployment system, the most critical of which can be exploited to escalate privilege to acquire root privileges.

Snaps are self-contained application deals that are developed to perform on functioning systems that use the Linux kernel and can be mounted working with a device known as snapd.

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Tracked as CVE-2021-44731, the issue concerns a privilege escalation flaw in the snap-confine perform, a application utilised internally by snapd to build the execution surroundings for snap programs. The shortcoming is rated 7.8 on the CVSS scoring method.

“Prosperous exploitation of this vulnerability enables any unprivileged consumer to acquire root privileges on the vulnerable host,” Bharat Jogi, director of vulnerability and risk analysis at Qualys, reported, including the weak spot could be abused to “get hold of complete root privileges on default installations of Ubuntu.”

Pink Hat, in an impartial advisory, described the issue as a “race problem” in the snap-confine component.

“A race issue in snap-confine exists when getting ready a non-public mount namespace for a snap,” the corporation observed. “This could allow for a nearby attacker to acquire root privileges by bind-mounting their possess contents inside the snap’s private mount namespace and causing snap-confine to execute arbitrary code and hence privilege escalation.”

Additionally found by the cybersecurity organization are 6 other flaws –

• CVE-2021-3995 – Unauthorized unmount in util-linux’s libmount
• CVE-2021-3996 – Unauthorized unmount in util-linux’s libmount
• CVE-2021-3997 – Uncontrolled recursion in systemd’s systemd-tmpfiles
• CVE-2021-3998 – Unpredicted return price from glibc’s realpath()
• CVE-2021-3999 – Off-by-one particular buffer overflow/underflow in glibc’s getcwd()
• CVE-2021-44730 – Hardlink attack in snap-confine’s sc_open up_snapd_software()

The vulnerability was documented to the Ubuntu security group on Oct 27, 2021, adhering to which patches have been released on February 17 as component of a coordinated disclosure system.

Qualys also pointed out that even though the flaw just isn’t remotely exploitable, an attacker that has logged in as an unprivileged consumer can “speedily” exploit the bug to gain root permissions, necessitating that the patches are used as shortly as feasible to mitigate probable threats.

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