SUSE SLED15 / SLES15 / openSUSE 15 Security Update : cosign (SUSE-SU-2023:4870-1)

medium Nessus Plugin ID 186996



The remote SUSE host is missing a security update.


The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 / openSUSE 15 host has a package installed that is affected by a vulnerability as referenced in the SUSE-SU-2023:4870-1 advisory.

- Cosign is a sigstore signing tool for OCI containers. Cosign is susceptible to a denial of service by an attacker controlled registry. An attacker who controls a remote registry can return a high number of attestations and/or signatures to Cosign and cause Cosign to enter a long loop resulting in an endless data attack. The root cause is that Cosign loops through all attestations fetched from the remote registry in pkg/cosign.FetchAttestations. The attacker needs to compromise the registry or make a request to a registry they control. When doing so, the attacker must return a high number of attestations in the response to Cosign. The result will be that the attacker can cause Cosign to go into a long or infinite loop that will prevent other users from verifying their data. In Kyvernos case, an attacker whose privileges are limited to making requests to the cluster can make a request with an image reference to their own registry, trigger the infinite loop and deny other users from completing their admission requests. Alternatively, the attacker can obtain control of the registry used by an organization and return a high number of attestations instead the expected number of attestations. The issue can be mitigated rather simply by setting a limit to the limit of attestations that Cosign will loop through. The limit does not need to be high to be within the vast majority of use cases and still prevent the endless data attack. This issue has been patched in version 2.2.1 and users are advised to upgrade.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.


Update the affected cosign package.

See Also

Plugin Details

Severity: Medium

ID: 186996

File Name: suse_SU-2023-4870-1.nasl

Version: 1.2

Type: local

Agent: unix

Published: 12/15/2023

Updated: 12/21/2023

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information


Risk Factor: Low

Score: 2.2


Risk Factor: Medium

Base Score: 5

Temporal Score: 3.9

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS Score Source: CVE-2023-46737


Risk Factor: Medium

Base Score: 5.3

Temporal Score: 4.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:novell:suse_linux:cosign, cpe:/o:novell:suse_linux:15

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/SuSE/release, Host/SuSE/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 12/14/2023

Vulnerability Publication Date: 11/7/2023

Reference Information

CVE: CVE-2023-46737

SuSE: SUSE-SU-2023:4870-1