CVE-2018-20217 Denial of service in n/a
Medium 5.3
Published
Updated
Check this codebase for CVE-2018-20217 and fix it if it is affected.
What it is: CVE-2018-20217 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 26 Dec 2018. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-20217 in the wild and no public exploit code.
Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2018-20217/ (Markdown: https://insights.sbomify.com/CVE-2018-20217/index.md)
An attacker with a legacy encryption ticket can crash the MIT Kerberos KDC by sending a specific S4U2Self request.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2018-20217?
CVE-2018-20217 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 26 Dec 2018. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A Reachable Assertion issue was discovered in the KDC in MIT Kerberos 5 (aka krb5) before 1.17. If an attacker can obtain a krbtgt ticket using an older encryption type (single-DES, triple-DES, or RC4), the attacker can crash the KDC by making an S4U2Self request.
Weakness: CWE-617
Which versions are affected by CVE-2018-20217?
It affects 2 products.
Linux distribution packages (40)
krb5 Red Hat:enterprise_linux:7::client | All versions | 0:1.15.1-37.el7_7.2 |
krb5-debuginfo Red Hat:enterprise_linux:7::client | All versions | 0:1.15.1-37.el7_7.2 |
krb5-devel Red Hat:enterprise_linux:7::client | All versions | 0:1.15.1-37.el7_7.2 |
krb5-libs Red Hat:enterprise_linux:7::client | All versions | 0:1.15.1-37.el7_7.2 |
krb5-pkinit Red Hat:enterprise_linux:7::client | All versions | 0:1.15.1-37.el7_7.2 |
krb5-server Red Hat:enterprise_linux:7::client | All versions | 0:1.15.1-37.el7_7.2 |
krb5-server-ldap Red Hat:enterprise_linux:7::client | All versions | 0:1.15.1-37.el7_7.2 |
krb5-workstation Red Hat:enterprise_linux:7::client | All versions | 0:1.15.1-37.el7_7.2 |
libkadm5 Red Hat:enterprise_linux:7::client | All versions | 0:1.15.1-37.el7_7.2 |
krb5 Red Hat:enterprise_linux:7::computenode | All versions | 0:1.15.1-37.el7_7.2 |
krb5-debuginfo Red Hat:enterprise_linux:7::computenode | All versions | 0:1.15.1-37.el7_7.2 |
krb5-devel Red Hat:enterprise_linux:7::computenode | All versions | 0:1.15.1-37.el7_7.2 |
krb5-libs Red Hat:enterprise_linux:7::computenode | All versions | 0:1.15.1-37.el7_7.2 |
krb5-pkinit Red Hat:enterprise_linux:7::computenode | All versions | 0:1.15.1-37.el7_7.2 |
krb5-server Red Hat:enterprise_linux:7::computenode | All versions | 0:1.15.1-37.el7_7.2 |
krb5-server-ldap Red Hat:enterprise_linux:7::computenode | All versions | 0:1.15.1-37.el7_7.2 |
krb5-workstation Red Hat:enterprise_linux:7::computenode | All versions | 0:1.15.1-37.el7_7.2 |
libkadm5 Red Hat:enterprise_linux:7::computenode | All versions | 0:1.15.1-37.el7_7.2 |
krb5 Red Hat:enterprise_linux:7::server | All versions | 0:1.15.1-37.el7_7.2 |
krb5-debuginfo Red Hat:enterprise_linux:7::server | All versions | 0:1.15.1-37.el7_7.2 |
krb5-devel Red Hat:enterprise_linux:7::server | All versions | 0:1.15.1-37.el7_7.2 |
krb5-libs Red Hat:enterprise_linux:7::server | All versions | 0:1.15.1-37.el7_7.2 |
krb5-pkinit Red Hat:enterprise_linux:7::server | All versions | 0:1.15.1-37.el7_7.2 |
krb5-server Red Hat:enterprise_linux:7::server | All versions | 0:1.15.1-37.el7_7.2 |
krb5-server-ldap Red Hat:enterprise_linux:7::server | All versions | 0:1.15.1-37.el7_7.2 |
krb5-workstation Red Hat:enterprise_linux:7::server | All versions | 0:1.15.1-37.el7_7.2 |
libkadm5 Red Hat:enterprise_linux:7::server | All versions | 0:1.15.1-37.el7_7.2 |
krb5 Red Hat:enterprise_linux:7::workstation | All versions | 0:1.15.1-37.el7_7.2 |
krb5-debuginfo Red Hat:enterprise_linux:7::workstation | All versions | 0:1.15.1-37.el7_7.2 |
krb5-devel Red Hat:enterprise_linux:7::workstation | All versions | 0:1.15.1-37.el7_7.2 |
krb5-libs Red Hat:enterprise_linux:7::workstation | All versions | 0:1.15.1-37.el7_7.2 |
krb5-pkinit Red Hat:enterprise_linux:7::workstation | All versions | 0:1.15.1-37.el7_7.2 |
krb5-server Red Hat:enterprise_linux:7::workstation | All versions | 0:1.15.1-37.el7_7.2 |
krb5-server-ldap Red Hat:enterprise_linux:7::workstation | All versions | 0:1.15.1-37.el7_7.2 |
krb5-workstation Red Hat:enterprise_linux:7::workstation | All versions | 0:1.15.1-37.el7_7.2 |
libkadm5 Red Hat:enterprise_linux:7::workstation | All versions | 0:1.15.1-37.el7_7.2 |
krb5 SUSE:Enterprise Storage 4 | All versions | 1.12.5-40.31.1 |
krb5 SUSE:Linux Enterprise Desktop 12 SP3 | All versions | 1.12.5-40.31.1 |
krb5 SUSE:Linux Enterprise Desktop 12 SP4 | All versions | 1.12.5-40.31.1 |
krb5 SUSE:Linux Enterprise Server 12 SP1-LTSS | All versions | 1.12.1-38.13.2 |
Products include Debian Debian Linux, Mit Kerberos.
How do I fix CVE-2018-20217?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2018-20217 being exploited?
There is no known exploitation of CVE-2018-20217 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as ALPINE-CVE-2018-20217, CLEANSTART-2024-EO56107, CLSA-2023-1675372649, DEBIAN-CVE-2018-20217, GHSA-f4hc-rvh5-8phv, MGASA-2019-0028 and 6 more.