Use-after-free in xen (Alpine package)



Risk Low
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2020-29483
CWE-ID CWE-416
Exploitation vector Local
Public exploit N/A
Vulnerable software
 IBM Systems Director
Server applications / Other server solutions

xen (Alpine package)
Operating systems & Components / Operating system package or component

Vendor IBM Corporation
Alpine Linux Development Team

Security Bulletin

This security bulletin contains one low risk vulnerability.

1) Use-after-free

EUVDB-ID: #VU49133

Risk: Low

CVSSv4.0: 5.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:U/U:Clear]

CVE-ID: CVE-2020-29483

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a local authenticated user to a crash the entire system.

An issue was discovered in Xen through 4.14.x. Xenstored and guests communicate via a shared memory page using a specific protocol. When a guest violates this protocol, xenstored will drop the connection to that guest. Unfortunately, this is done by just removing the guest from xenstored's internal management, resulting in the same actions as if the guest had been destroyed, including sending an @releaseDomain event. @releaseDomain events do not say that the guest has been removed. All watchers of this event must look at the states of all guests to find the guest that has been removed. When an @releaseDomain is generated due to a domain xenstored protocol violation, because the guest is still running, the watchers will not react. Later, when the guest is actually destroyed, xenstored will no longer have it stored in its internal data base, so no further @releaseDomain event will be sent. This can lead to a zombie domain; memory mappings of that guest's memory will not be removed, due to the missing event. This zombie domain will be cleaned up only after another domain is destroyed, as that will trigger another @releaseDomain event. If the device model of the guest that violated the Xenstore protocol is running in a stub-domain, a use-after-free case could happen in xenstored, after having removed the guest from its internal data base, possibly resulting in a crash of xenstored. A malicious guest can block resources of the host for a period after its own death. Guests with a stub domain device model can eventually crash xenstored, resulting in a more serious denial of service (the prevention of any further domain management operations). Only the C variant of Xenstore is affected; the Ocaml variant is not affected. Only HVM guests with a stubdom device model can cause a serious DoS.

Mitigation

Install update from vendor's website.

Vulnerable software versions

IBM Systems Director: 6.3.2.2

xen (Alpine package): 1.42

xen (Alpine package): 1.1.7-0ubuntu1 - 1.2.3-0ubuntu2.7

xen (Alpine package): 3.0.8-1 - 3.0.13-1

xen (Alpine package): 2:1.3.2-2ubuntu0.1

xen (Alpine package): 1:6.2.3-5

xen (Alpine package): 0.11-4

xen (Alpine package): 3.2.21-1

xen (Alpine package): 1.88-1

xen (Alpine package): 0.2.3.2-1

xen (Alpine package): 0.101 - 0.102ubuntu1

xen (Alpine package): 0.1.0-0ubuntu1 - 0.1.5-0ubuntu1

xen (Alpine package): 3.1-1 - 3.1-2

xen (Alpine package): 1.3.1-1 - 1.3.1-2

xen (Alpine package): 3.1-1

xen (Alpine package): 0.18.1.1-9ubuntu1

xen (Alpine package): 4.63-15

xen (Alpine package): 3.1.6.1-1

xen (Alpine package): 2.55-2 - 2.72-1

xen (Alpine package): 2.2.0.3-2ubuntu5

xen (Alpine package): 3.5.11.2003.06.04-3

xen (Alpine package): 5.4-2ubuntu1

xen (Alpine package): 5.4b-1

xen (Alpine package): 0.15

xen (Alpine package): 0.18ubuntu0.2 - 0.32

xen (Alpine package): 0.3.6.0amd12 - 1.12.9

xen (Alpine package): 1.9.9-3 - 1.9.10-1

xen (Alpine package): 0.48-4

xen (Alpine package): 0.9b-20040421-1 - 1.1-20120215-2

xen (Alpine package): 0.16 - 0.35

xen (Alpine package): 0.2 - 0.9

xen (Alpine package): 0.4

xen (Alpine package): 2.5.3 - 2.17.5ubuntu1

xen (Alpine package): 3.4.0-1

xen (Alpine package): 0.14-1 - 0.15-2

xen (Alpine package): 2014.1-3

xen (Alpine package): 24.0-0ubuntu1

xen (Alpine package): 0.5.2-0ubuntu1 - 1.2.5ubuntu1daily13.06.14-0ubuntu1

xen (Alpine package): 3.0-0ubuntu1

xen (Alpine package): 1.5.2 - 1.6.2

xen (Alpine package): 0.1.8 - 1.0.75

xen (Alpine package): 1.20.0 - 2.18.2

xen (Alpine package): 20081029ubuntu63 - 20101020ubuntu468

xen (Alpine package): 0.74 - 9.20160115

xen (Alpine package): 0.2.12 - 1.5.49

xen (Alpine package): 1.8.8-2ubuntu1

xen (Alpine package): 0.2.8-8 - 0.2.11-1

xen (Alpine package): 0.3 - 1.8.42

xen (Alpine package): 5.3.28-3 - 5.3.28-4

xen (Alpine package): 1.5

xen (Alpine package): 0.4.5 - 0.5.8-2.2

xen (Alpine package): 0.2.11-1build1

xen (Alpine package): 0.63

xen (Alpine package): 0.3.1-0ubuntu1 - 0.10.0-3

xen (Alpine package): 0.13-1 - 0.22.1-2

xen (Alpine package): 2.1.0-2 - 2.1.26.dfsg1-14

xen (Alpine package): 0.5.16-3.5ubuntu1 - 0.5.17-6

xen (Alpine package): 1.3-1 - 1.3-3

xen (Alpine package): 5.11-1 - 7.35.0-1

xen (Alpine package): 1.3.9-17 - 2.0.3-2

xen (Alpine package): 0.1.2-1 - 0.2.6-1ubuntu1

xen (Alpine package): 1.0.47-2 - 1.0.64-0ubuntu1

xen (Alpine package): 2.1-3-dfsg-1 - 2.1-3-dfsg-2

xen (Alpine package): 0.100-3

xen (Alpine package): 2:1.0.6-2ubuntu7 - 2:1.6.4-1

xen (Alpine package): 0.8 - 9ubuntu2

xen (Alpine package): 3.0pl1-50 - 3.0pl1-119

xen (Alpine package): 1.0.0-0ubuntu1 - 1.0.0-0ubuntu2

xen (Alpine package): expression - 7.1.1-1

xen (Alpine package): 2.8.13-7 - 2.8.13-10

xen (Alpine package): 2.4.2-16 - 2.7-1

xen (Alpine package): 0.92-0ubuntu3 - 0.98-1

xen (Alpine package): 4.5.7-1 - 8.20-3ubuntu4

xen (Alpine package): 0.2.10-3 - 0.4.6-3

xen (Alpine package): 1.5 - 1.141

xen (Alpine package): 1:0.8.6-0ubuntu4 - 1:0.9.7.6-0ubuntu2

xen (Alpine package): 0.3ubuntu7 - 0.3ubuntu15.2

xen (Alpine package): 1.2.12-1ubuntu1 - 1.2.12-1

xen (Alpine package): 0.7-svn20050721 - 1.4.29-1

xen (Alpine package): 2.8.12.1-1.6 - 3.9.0-1

xen (Alpine package): 1.0.5-2 - 1.0.8-3

xen (Alpine package): 0.25-0ubuntu1 - 0.25-0ubuntu3

xen (Alpine package): 0.9-0ubuntu1 - 0.12-0ubuntu1

xen (Alpine package): 1.4.4

xen (Alpine package): 2.2.15-1

xen (Alpine package): 1.4.2

xen (Alpine package): 4.8.9

xen (Alpine package): 3.0.4

xen (Alpine package): 2.1.0

xen (Alpine package): 1.4.17

xen (Alpine package): 2.2.0b2

xen (Alpine package): r12.0 nil

xen (Alpine package): 3.0

xen (Alpine package):

xen (Alpine package): before 4.14.1-r0

CPE2.3 External links

https://git.alpinelinux.org/aports/commit/?id=1f5fe5eb0e0bb4588f6b1b8b4e1563293acbb087


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.



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