Privilege escalation in xen (Alpine package)

1) Privilege escalation

EUVDB-ID: #VU12450

Risk: Low

CVSSv4.0: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Clear]

CVE-ID: CVE-2018-8897

CWE-ID: CWE-703 - Improper Check or Handling of Exceptional Conditions

Exploit availability: Yes

Description

The vulnerability allows a local attacker to gain elevated privileges on the target system.

The vulnerability exists due to improper implementation of Intel 64 and IA-32 Architectures Software Developer's Manual (SDM) on multiple system kernels, which results in an unexpected behavior for #DB exceptions that are deferred by MOV SS or POP SS. A local user can execute arbitrary code with elevated privileges.

Mitigation

Install update from vendor's website.

Vulnerable software versions

xen (Alpine package): 4.6.6-r4

CPE2.3

• cpe:2.3:o:alpine:xen_alpine_package:4.6.6-r4:*:*:*:*:alpine_linux:*:3.3

External links

https://git.alpinelinux.org/aports/commit/?id=cf5828feef63ab62588f29482b15001535c73719
https://git.alpinelinux.org/aports/commit/?id=66ff4f8a6b71dd204bc568c21c45941d612402c2
https://git.alpinelinux.org/aports/commit/?id=96018bf2841ac59b632f6d84ad6247b5b825dc3a
https://git.alpinelinux.org/aports/commit/?id=5f72054ca4ac3f0f8f05c17a83a9c203f580bddc
https://git.alpinelinux.org/aports/commit/?id=d2a71459869989207ef392e3d8338330ee055a7f
https://git.alpinelinux.org/aports/commit/?id=9a8ee8c0046132a4ccaab5cffc615967367db70d
https://git.alpinelinux.org/aports/commit/?id=9bdda5f2061773ab7f74bacd75ba922ce5fef8ac

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. However, a fully functional exploit for this vulnerability is available.