Impact

A failure in the update logic of Rancher's admission Webhook may lead to the misconfiguration of the Webhook. This component enforces validation rules and security checks before resources are admitted into the Kubernetes cluster.

When the Webhook is operating in a degraded state, it no longer validates any resources, which may result in severe privilege escalations and data corruption.

The issue only affects users that upgrade from 2.6.x or 2.7.x to 2.7.2. Users that did a fresh install of 2.7.2 (and did not follow an upgrade path) are not affected.

The command below can be executed on the local cluster to determine whether the cluster is affected by this issue:

sh $ kubectl get validatingwebhookconfigurations.admissionregistration.k8s.io rancher.cattle.io

NAME WEBHOOKS AGE rancher.cattle.io 0 19h

If the resulting webhook quantity is 0, the Rancher instance is affected.

Patches

Patched versions include release 2.7.3 and later versions.

Workarounds

If you are affected and cannot update to a patched Rancher version, the recommended workaround is to manually reconfigure the Webhook with the script below. Please note that the script must be run from inside the local cluster or with a kubeconfig pointing to the local cluster which has admin permissions.

yaml #!/bin/bash

set -euo pipefail

function prereqs() { if ! [ -x "$(command -v kubectl)" ]; then echo "error: kubectl is not installed." >&2 exit 1 fi

if [[ -z "$(kubectl config view -o jsonpath='{.clusters[].cluster.server}')" ]]; then echo "error: No kubernetes cluster found on kubeconfig." >&2 exit 1 fi }

function restartdeployment(){ kubectl rollout restart deployment rancher-webhook -n cattle-system kubectl rollout status deployment rancher-webhook -n cattle-system --timeout=30s }

function workaround() { echo "Cluster: $(kubectl config view -o jsonpath='{.clusters[].cluster.server}')"

if ! kubectl get validatingwebhookconfigurations.admissionregistration.k8s.io rancher.cattle.io > /dev/null 2>&1; then echo "webhook rancher.cattle.io not found, restarting deployment:" restartdeployment

echo "waiting for webhook configuration" sleep 15s fi

local -i webhooks webhooks="$(kubectl get validatingwebhookconfigurations.admissionregistration.k8s.io rancher.cattle.io --no-headers | awk '{ print $2 }')"

if [ "${webhooks}" == "0" ]; then echo "Webhook misconfiguration status: Cluster is affected by CVE-2023-22651" echo "Running workaround:" kubectl delete validatingwebhookconfiguration rancher.cattle.io restartdeployment

ret=$? if [ $ret -eq 0 ]; then echo "Webhook restored, CVE-2023-22651 is fixed" else echo "error trying to restart deployment. try again in a few seconds." fi else echo "Webhook misconfiguration status: not present (skipping)" fi

echo "Done" }

function main() { prereqs workaround }

main

References - https://github.com/rancher/webhook/pull/216/commits/a4a498613b43a3ee93c5ab06742a3bc8adace45d

For more information If you have any questions or comments about this advisory:

- Reach out to the SUSE Rancher Security team for security related inquiries. - Open an issue in the Rancher repository. - Verify our support matrix and product support lifecycle.

Impact

A vulnerability has been identified which enables Standard users or above to elevate their permissions to Administrator in the local cluster.

The local cluster means the cluster where Rancher is installed. It is named local inside the list of clusters in the Rancher UI.

Standard users could leverage their existing permissions to manipulate Kubernetes secrets in the local cluster, resulting in the secret being deleted, but their read-level permissions to the secret being preserved. When this operation was followed-up by other specially crafted commands, it could result in the user gaining access to tokens belonging to service accounts in the local cluster.

Users that have custom global roles which grant create and delete permissions on secrets would also be able to exploit this vulnerability.

Users with audit logs enabled in Rancher can try to identify possible abuses of this issue by going through the logs. To sieve through the data filter by kind: Secret with type: provisioning.cattle.io/cloud-credential, then investigate all log entries that affect that specific resource. A secondary check would be to filter by all operations with Opaque Secrets within the cattle-global-data namespace.

After patching, it is recommended that users review access methods to Rancher (including RBAC policies, tokens, and host-level node access), to ensure that no changes were made to persist access to users who have leveraged this vulnerability.

Patches

Patched versions include releases 2.6.13, 2.7.4 and later versions.

Workarounds

There is no direct mitigation besides updating Rancher to a patched version.

For more information

If you have any questions or comments about this advisory:

- Reach out to the SUSE Rancher Security team for security related inquiries. - Open an issue in the Rancher repository. - Verify with our support matrix and product support lifecycle.

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Format string vulnerability in logging function of ypbind 3.3, while running in debug mode, leaks file descriptors and allows an attacker to cause a denial of service.

Format string vulnerability in ypbind-mt in SuSE SuSE-6.2, and possibly other Linux operating systems, allows an attacker to gain root privileges.

Some functions that implement the locale subsystem on Unix do not properly cleanse user-injected format strings, which allows local attackers to execute arbitrary commands via functions such as gettext and catopen.

String parsing error in rpc.kstatd in the linuxnfs or knfsd packages in SuSE and possibly other Linux systems allows remote attackers to gain root privileges.

rpc.statd in the nfs-utils package in various Linux distributions does not properly cleanse untrusted format strings, which allows remote attackers to gain root privileges.

Tnef program in Linux systems allows remote attackers to overwrite arbitrary files via TNEF encoded compressed attachments which specify absolute path names for the decompressed output.

Buffer overflow in the XDMCP parsing code of GNOME gdm, KDE kdm, and wdm allows remote attackers to execute arbitrary commands or cause a denial of service via a long FORWARDQUERY request.

SuSE Linux IMAP server allows remote attackers to bypass IMAP authentication and gain privileges.

Xpdf, as used in products such as gpdf, kpdf, pdftohtml, poppler, teTeX, CUPS, libextractor, and others, allows attackers to cause a denial of service (infinite loop) via streams that end prematurely, as demonstrated using the (1) CCITTFaxDecode and (2) DCTDecode streams, aka "Infinite CPU spins."

The sendpinentryenvironment function in asshelp.c in gpg2 on SUSE Linux 9.3 does not properly handle certain options, which can prevent pinentry from being found and causes S/MIME signing to fail.

Off-by-one error in the channel code of OpenSSH 2.0 through 3.0.2 allows local users or remote malicious servers to gain privileges.

Integer overflow in the Samba daemon (smbd) in Samba 2.x and 3.0.x through 3.0.9 allows remote authenticated users to cause a denial of service (application crash) and possibly execute arbitrary code via a Samba request with a large number of security descriptors that triggers a heap-based buffer overflow.

Buffer overflow in unarj before 2.63a-r2 allows remote attackers to execute arbitrary code via an arj archive that contains long filenames.

Multiple integer overflows in xpdf 3.0, and other packages that use xpdf code such as CUPS, allow remote attackers to cause a denial of service (crash) and possibly execute arbitrary code, a different set of vulnerabilities than those identified by CVE-2004-0888.

Heap-based buffer overflow in the OJPEGVSetField function in tifojpeg.c for libtiff 3.6.1 and earlier, when compiled with the OJPEGSUPPORT (old JPEG support) option, allows remote attackers to execute arbitrary code via a malformed TIFF image.

Stack-based buffer overflow in the writeGroup function in nsVCardObj.cpp for Mozilla Firefox before the Preview Release, Mozilla before 1.7.3, and Thunderbird before 0.8 allows remote attackers to execute arbitrary code via malformed VCard attachments that are not properly handled when previewing a message.

Multiple integer overflows in xpdf 2.0 and 3.0, and other packages that use xpdf code such as CUPS, gpdf, and kdegraphics, allow remote attackers to cause a denial of service (crash) and possibly execute arbitrary code, a different set of vulnerabilities than those identified by CVE-2004-0889.

Multiple heap-based buffer overflows in Mozilla Firefox before the Preview Release, Mozilla before 1.7.3, and Thunderbird before 0.8 allow remote attackers to cause a denial of service (application crash) or execute arbitrary code via (1) the "Send page" functionality, (2) certain responses from a malicious POP3 server, or (3) a link containing a non-ASCII hostname.

Multiple vulnerabilities in libXpm for 6.8.1 and earlier, as used in XFree86 and other packages, include (1) multiple integer overflows, (2) out-of-bounds memory accesses, (3) directory traversal, (4) shell metacharacter, (5) endless loops, and (6) memory leaks, which could allow remote attackers to obtain sensitive information, cause a denial of service (application crash), or execute arbitrary code via a certain XPM image file. NOTE: it is highly likely that this candidate will be SPLIT into other candidates in the future, per CVE's content decisions.

Buffer overflow in the EXIF parsing routine in ImageMagick before 6.1.0 allows remote attackers to execute arbitrary code via a certain image file.

Integer overflow in GD Graphics Library libgd 2.0.28 (libgd2), and possibly other versions, allows remote attackers to cause a denial of service and possibly execute arbitrary code via PNG image files with large image rows values that lead to a heap-based buffer overflow in the gdImageCreateFromPngCtx function, a different set of vulnerabilities than CVE-2004-0941.

a2ps 4.13 allows remote attackers to execute arbitrary commands via shell metacharacters in the filename.

The Live CD in SUSE LINUX 9.1 Personal edition is configured without a password for root, which allows remote attackers to gain privileges via SSH.

Multiple unspecified vulnerabilities in OpenPBS, as used in SUSE Linux 9.2 through 10.1, allow attackers to execute arbitrary code via unspecified vectors.

Buffer overflow in the logging capability for the DHCP daemon (DHCPD) for ISC DHCP 3.0.1rc12 and 3.0.1rc13 allows remote attackers to cause a denial of service (server crash) and possibly execute arbitrary code via multiple hostname options in (1) DISCOVER, (2) OFFER, (3) REQUEST, (4) ACK, or (5) NAK messages, which can generate a long string when writing to a log file.

The DHCP daemon (DHCPD) for ISC DHCP 3.0.1rc12 and 3.0.1rc13, when compiled in environments that do not provide the vsnprintf function, uses C include files that define vsnprintf to use the less safe vsprintf function, which can lead to buffer overflow vulnerabilities that enable a denial of service (server crash) and possibly execute arbitrary code.

Mozilla Firefox before 3.6.26 and 4.x through 9.0, Thunderbird before 3.1.18 and 5.0 through 9.0, and SeaMonkey before 2.7 do not properly initialize nsChildView data structures, which allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via a crafted Ogg Vorbis file.