Vulnerability identifier: #VU62797

Vulnerability risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-20291

CWE-ID: CWE-667

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Storage
Server applications / Other server solutions

Vendor:

Description

The vulnerability allows a local user to perform a denial of service attack (DoS) on the target system.

The vulnerability exists due to double-locking error. When a container image is processed, each layer is unpacked using `tar`. If one of those layers is not a valid `tar` archive this causes an error leading to an unexpected situation where the code indefinitely waits for the tar unpacked stream, which never finishes. An attacker could use this vulnerability to craft a malicious image, which when downloaded and stored by an application using containers/storage, would then cause a deadlock leading to a Denial of Service (DoS).

Mitigation
Install updates from vendor's website.

Vulnerable software versions

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External links
http://bugzilla.redhat.com/show_bug.cgi?id=1939485
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/R5D7XL7FL24TWFMGQ3K2S72EOUSLZMKL/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZNMB7O2UIXE34PGSCSOULGHPX5LIJBMM/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WX24EITRXVHDM5M223BVTJA2ODF2FSHI/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SPYOHNG2Q7DCAQZMGYLMENLKALGDLG3X/
http://unit42.paloaltonetworks.com/cve-2021-20291/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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