A bug in the 9p authentication implementation within lib9p allows an attacker with an existing valid user within the configured auth server to impersonate any other valid filesystem user.

This is due to lib9p not properly verifying that the uname given in the Tauth and Tattach 9p messages matches the client UID returned from the factotum authentication handshake.


The only filesystem making use of these functions within the base 9front systems is the experimental hjfs disk filesystem, other disk filesystems (cwfs and gefs) are not affected by this bug.

This bug was inherited from Plan 9 and is present in all versions of 9front and is remedied fully in commit 9645ae07eb66a59015e3e118d0024790c37400da.
Advisories
Source ID Title
EUVD EUVD EUVD-2024-48983 A bug in the 9p authentication implementation within lib9p allows an attacker with an existing valid user within the configured auth server to impersonate any other valid filesystem user. This is due to lib9p not properly verifying that the uname given in the Tauth and Tattach 9p messages matches the client UID returned from the factotum authentication handshake. The only filesystem making use of these functions within the base 9front systems is the experimental hjfs disk filesystem, other disk filesystems (cwfs and gefs) are not affected by this bug. This bug was inherited from Plan 9 and is present in all versions of 9front and is remedied fully in commit 9645ae07eb66a59015e3e118d0024790c37400da.
Fixes

Solution

Update 9front to at least commit 9645ae07eb66a59015e3e118d0024790c37400da and follow these update instructions: 1. Make and install the now patched version of lib9p. 2. Make and install the new patched version of hjfs. 3. Make and install the kernel to include the patched hjfs within the kernel's paqfs.


Workaround

No workaround given by the vendor.

History

Thu, 12 Sep 2024 21:15:00 +0000

Type Values Removed Values Added
First Time appeared 9front lib9p
CPEs cpe:2.3:a:9front:lib9p:*:*:*:*:*:*:*:*
Vendors & Products 9front lib9p
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'}


Mon, 26 Aug 2024 16:30:00 +0000

Type Values Removed Values Added
First Time appeared 9front
9front 9front
CPEs cpe:2.3:a:9front:9front:*:*:*:*:*:*:*:*
Vendors & Products 9front
9front 9front
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sun, 25 Aug 2024 21:45:00 +0000

Type Values Removed Values Added
Description A bug in the 9p authentication implementation within lib9p allows an attacker with an existing valid user within the configured auth server to impersonate any other valid filesystem user. This is due to lib9p not properly verifying that the uname given in the Tauth and Tattach 9p messages matches the client UID returned from the factotum authentication handshake. The only filesystem making use of these functions within the base 9front systems is the experimental hjfs disk filesystem, other disk filesystems (cwfs and gefs) are not affected by this bug. This bug was inherited from Plan 9 and is present in all versions of 9front and is remedied fully in commit 9645ae07eb66a59015e3e118d0024790c37400da.
Title User impersonation for lib9p based 9p fileservers
Weaknesses CWE-639
References
Metrics cvssV4_0

{'score': 8.8, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/AU:N/V:C/RE:L/U:Red'}


cve-icon MITRE

Status: PUBLISHED

Assigner: 9front

Published:

Updated: 2024-08-26T15:22:18.885Z

Reserved: 2024-08-25T21:25:59.746Z

Link: CVE-2024-8158

cve-icon Vulnrichment

Updated: 2024-08-26T15:22:10.520Z

cve-icon NVD

Status : Analyzed

Published: 2024-08-25T22:15:05.903

Modified: 2024-09-12T21:00:00.573

Link: CVE-2024-8158

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.