Race condition in php7 (Alpine package)

1) Race condition

EUVDB-ID: #VU21220

Risk: Low

CVSSv4.0: 1.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2019-9637

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

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a race condition when renaming files on the system, as the rename() PHP function temporary creates files with weak privileges. A local user can exploit this behavior to gain access to sensitive information.

Mitigation

Install update from vendor's website.

Vulnerable software versions

php7 (Alpine package): 7.1.17-r0 - 7.2.13-r0

CPE2.3

• cpe:2.3:o:alpine:php7_alpine_package:7.1.17-r0:*:*:*:*:alpine_linux:*:3.6
• cpe:2.3:o:alpine:php7_alpine_package:7.1.30-r0:*:*:*:*:alpine_linux:*:3.6
• cpe:2.3:o:alpine:php7_alpine_package:7.1.32-r0:*:*:*:*:alpine_linux:*:3.7

External links

https://git.alpinelinux.org/aports/commit/?id=ebcd3398f2d6e6f536fbfeaba9cc3b84ac377251
https://git.alpinelinux.org/aports/commit/?id=583c0d55e9e7208425dd53eb1739a7010b6b0dbc
https://git.alpinelinux.org/aports/commit/?id=7c1daf27a04307093cef0fcb3f1c5ab4bb68eee1
https://git.alpinelinux.org/aports/commit/?id=d42b915a2245405763bb485ededfbdb01393f109

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.