NULL pointer dereference in xen (Alpine package)



Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2020-29484
CWE-ID CWE-476
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 medium risk vulnerability.

1) NULL pointer dereference

EUVDB-ID: #VU49134

Risk: Medium

CVSSv4.0: 1.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:H/E:U/U:Green]

CVE-ID: CVE-2020-29484

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error. A remote attacker can trigger denial of service conditions via Xenstore messages, consisting of a message header and the payload. The payload length is limited to 4096 bytes. Any request to xenstored resulting in a response with a payload longer than 4096 bytes will result in an error. When registering a watch, the payload length limit applies to the combined length of the watched path and the specified tag. Because watches for a specific path are also triggered for all nodes below that path, the payload of a watch event message can be longer than the payload needed to register the watch. A malicious guest that registers a watch using a very large tag (i.e., with a registration operation payload length close to the 4096 byte limit) can cause the generation of watch events with a payload length larger than 4096 bytes, by writing to Xenstore entries below the watched path. This will result in an error condition in xenstored. This error can result in a NULL pointer dereference, leading to a crash of xenstored. A malicious guest administrator can cause xenstored to crash, leading to a denial of service. Following a xenstored crash, domains may continue to run, but management operations will be impossible. Only C xenstored is affected, oxenstored is not affected.

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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