QID 376419

Date Published: 2022-02-17

QID 376419: Snap-Confine Local Privilege Escalation Vulnerability (Oh Snap! More Lemmings)

We have discovered Multiple Vulnerabilities in Linux's snap-confine, a program used internally by snapd to construct the execution environment for snap applications. Snap is a software packaging and deployment system used on Linux Distributions and MacOS.

Here is the list of CVEs' related to this:
CVE-2021-44730: Hardlink attack in snap-confine's sc_open_snapd_tool()
CVE-2021-44731: Race condition in snap-confine's setup_private_mount()
CVE-2021-3996: Unauthorized unmount in util-linux's libmount
CVE-2021-3995: Unauthorized unmount in util-linux's libmount
CVE-2021-3998: Unexpected return value from glibc's realpath()
CVE-2021-3999: Off-by-one buffer overflow/underflow in glibc's getcwd()
and CVE-2021-3997: Uncontrolled recursion in systemd's systemd-tmpfiles

Affected Versions:
As of now, all the versions of snap package manager are vulnerable

QID Detection Logic:
The authenticated QID checks for the Snap package by running the command "snap version" on Linux Distributions and MacOS

Successful exploitation of this vulnerability allows any unprivileged user to gain root privileges on the vulnerable host.

  • CVSS V3 rated as Critical - 8.8 severity.
  • CVSS V2 rated as High - 6.9 severity.
    • Solution

    Customers are advised to apply the latest patches.

    Vendor References

    CVEs related to QID 376419

    CVE-2021-44731 | CVE-2021-44730 | CVE-2021-3996 | CVE-2021-3995 | CVE-2021-3998 | CVE-2021-3999 | CVE-2021-3997 |
    Software Advisories
    Advisory ID Software Component Link
    snap-confine Linux Local Privilege Escalation Vulnerability URL Logo security.ubuntu.com/ubuntu/pool/main/s/snapd/?C=M;O=D
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