# CVE-2015-7704: Denial of service in n/a > Remote attackers can cause a denial of service in the NTP daemon by sending crafted KOD messages, requiring an upgrade to patched versions. - **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 7 Aug 2017 - **Updated:** 6 Aug 2024 - **Also known as:** DEBIAN-CVE-2015-7704, GHSA-jm9v-x8m5-p6p2, RHSA-2015:2520, UBUNTU-CVE-2015-7704 ## What is CVE-2015-7704? CVE-2015-7704 is a high-severity denial of service vulnerability in Citrix Xenserver, published on 7 Aug 2017. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description The ntpd client in NTP 4.x before 4.2.8p4 and 4.3.x before 4.3.77 allows remote attackers to cause a denial of service via a number of crafted "KOD" messages. Weakness: CWE-20 (Improper Input Validation) ## Which versions are affected by CVE-2015-7704? It affects 14 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `ntp` | Red Hat:rhel_eus:6.5::computenode | All versions | 0:4.2.6p5-2.el6_5.1 | | `ntp-debuginfo` | Red Hat:rhel_eus:6.5::computenode | All versions | 0:4.2.6p5-2.el6_5.1 | | `ntp-doc` | Red Hat:rhel_eus:6.5::computenode | All versions | 0:4.2.6p5-2.el6_5.1 | | `ntp-perl` | Red Hat:rhel_eus:6.5::computenode | All versions | 0:4.2.6p5-2.el6_5.1 | | `ntpdate` | Red Hat:rhel_eus:6.5::computenode | All versions | 0:4.2.6p5-2.el6_5.1 | | `ntp` | Red Hat:rhel_eus:6.5::server | All versions | 0:4.2.6p5-2.el6_5.1 | | `ntp-debuginfo` | Red Hat:rhel_eus:6.5::server | All versions | 0:4.2.6p5-2.el6_5.1 | | `ntp-doc` | Red Hat:rhel_eus:6.5::server | All versions | 0:4.2.6p5-2.el6_5.1 | | `ntp-perl` | Red Hat:rhel_eus:6.5::server | All versions | 0:4.2.6p5-2.el6_5.1 | | `ntpdate` | Red Hat:rhel_eus:6.5::server | All versions | 0:4.2.6p5-2.el6_5.1 | | `ntp` | Red Hat:rhel_eus:6.6::computenode | All versions | 0:4.2.6p5-3.el6_6.1 | | `ntp-debuginfo` | Red Hat:rhel_eus:6.6::computenode | All versions | 0:4.2.6p5-3.el6_6.1 | | `ntp-doc` | Red Hat:rhel_eus:6.6::computenode | All versions | 0:4.2.6p5-3.el6_6.1 | | `ntp-perl` | Red Hat:rhel_eus:6.6::computenode | All versions | 0:4.2.6p5-3.el6_6.1 | | `ntpdate` | Red Hat:rhel_eus:6.6::computenode | All versions | 0:4.2.6p5-3.el6_6.1 | | `ntp` | Red Hat:rhel_eus:6.6::server | All versions | 0:4.2.6p5-3.el6_6.1 | | `ntp-debuginfo` | Red Hat:rhel_eus:6.6::server | All versions | 0:4.2.6p5-3.el6_6.1 | | `ntp-doc` | Red Hat:rhel_eus:6.6::server | All versions | 0:4.2.6p5-3.el6_6.1 | | `ntp-perl` | Red Hat:rhel_eus:6.6::server | All versions | 0:4.2.6p5-3.el6_6.1 | | `ntpdate` | Red Hat:rhel_eus:6.6::server | All versions | 0:4.2.6p5-3.el6_6.1 | Products: Citrix Xenserver, Debian Debian Linux, Mcafee Enterprise Security Manager, Netapp Clustered Data Ontap, Netapp Data Ontap, Netapp Oncommand Performance Manager, Netapp Oncommand Unified Manager, Ntp Ntp, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Server, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Eus, Redhat Enterprise Linux Server Tus, Redhat Enterprise Linux Workstation. ## How do I fix CVE-2015-7704? Upgrade to a fixed version. ## Is CVE-2015-7704 being exploited? There is no known exploitation of CVE-2015-7704 in the wild and no public exploit code. ## Other vulnerabilities in Citrix Xenserver - [CVE-2014-4947](https://insights.sbomify.com/CVE-2014-4947/): Memory corruption in n/a (critical 10.0) - [CVE-2018-14007](https://insights.sbomify.com/CVE-2018-14007/): Path traversal in n/a (critical 9.8) - [CVE-2015-7705](https://insights.sbomify.com/CVE-2015-7705/): Denial of service in n/a (critical 9.8) - [CVE-2016-5302](https://insights.sbomify.com/CVE-2016-5302/): Auth bypass in n/a (critical 9.8) - [CVE-2017-12134](https://insights.sbomify.com/CVE-2017-12134/): Memory corruption in n/a (high 8.8) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2015-7704 and fix it if it is affected. What it is: CVE-2015-7704 is a high-severity denial of service vulnerability in Citrix Xenserver, published on 7 Aug 2017. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2015-7704 in the wild and no public exploit code. Affected product: Citrix Xenserver. 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-2015-7704/ (Markdown: https://insights.sbomify.com/CVE-2015-7704/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2015-7704 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2015-7704 - OSV: https://osv.dev/vulnerability/CVE-2015-7704 --- From sbomify Insights: https://insights.sbomify.com/CVE-2015-7704/ Summaries are generated and may contain mistakes; the official description above is the record.