PT-2018-17633 · Linux · Fscrypt

Mark + 1 · Published 2018-08-23 · Updated 2021-06-23 · CVE-2018-6558

Positive Technologies (AI Summary)

CVSS v3.1

6.5

Medium

Base vector

AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Name of the Vulnerable Software and Affected Versions fscrypt versions prior to 0.2.4

Description The issue concerns the pam fscrypt module in fscrypt, which may incorrectly restore primary and supplementary group IDs to the values associated with the root user. This allows attackers to gain privileges via a successful login through certain applications that use Linux-PAM. Specifically, after dropping and then elevating process privileges, the euid, guid, and groups are not properly restored to their original values, allowing an unprivileged user to gain membership in the root group.

Recommendations For versions prior to 0.2.4, update to version 0.2.4 or later to resolve the issue. As a temporary workaround, consider restricting the use of the pam fscrypt module until a patch is available. Avoid using applications that rely on Linux-PAM for authentication until the issue is resolved.

Fix

Related Identifiers

CVE-2018-6558

GHSA-QJ26-7GRJ-WHG3

GO-2020-0027

Affected Products

Fscrypt

References · 15

• https://github.com/google/fscrypt/commit/315f9b042237200174a1fb99427f74027e191d66 · Patch
• https://github.com/google/fscrypt/commit/3022c1603d968c22f147b4a2c49c4637dd1be91b · Patch
• https://osv.dev/vulnerability/CVE-2018-6558 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2018-6558 · Security Note
• https://osv.dev/vulnerability/UBUNTU-CVE-2018-6558 · Vendor Advisory
• https://osv.dev/vulnerability/GO-2020-0027 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2018-6558 · Vendor Advisory
• https://launchpad.net/bugs/1787548 · Patch
• https://ubuntu.com/security/CVE-2018-6558 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2018-6558 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2018-6558 · Security Note
• https://osv.dev/vulnerability/GHSA-qj26-7grj-whg3 · Vendor Advisory
• https://github.com/google/fscrypt/issues/77 · Note
• https://github.com/google/fscrypt · Note
• https://pkg.go.dev/vuln/GO-2020-0027 · Note