Race condition in sddm (Alpine package)

1) Race condition

EUVDB-ID: #VU48419

Risk: Low

CVSSv4.0: 4.1 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2020-28049

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Exploit availability: No

Description

The vulnerability allows a local authenticated user to read and manipulate data.

An issue was discovered in SDDM before 0.19.0. It incorrectly starts the X server in a way that - for a short time period - allows local unprivileged users to create a connection to the X server without providing proper authentication. A local attacker can thus access X server display contents and, for example, intercept keystrokes or access the clipboard. This is caused by a race condition during Xauthority file creation.

Mitigation

Install update from vendor's website.

Vulnerable software versions

sddm (Alpine package): 0.18.1-r0 - 0.18.1-r9

CPE2.3

• cpe:2.3:o:alpine:sddm_alpine_package:0.18.1-r0:*:*:*:*:alpine_linux:*:3.10
• cpe:2.3:o:alpine:sddm_alpine_package:0.18.1-r1:*:*:*:*:alpine_linux:*:3.10
• cpe:2.3:o:alpine:sddm_alpine_package:0.18.1-r2:*:*:*:*:alpine_linux:*:3.10

External links

https://git.alpinelinux.org/aports/commit/?id=1d651a701f846a02586af0a0b17767c05f8e44fe

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.