CVE-2009-3563
ntp_request.c in ntpd in NTP before 4.2.4p8, and 4.2.5, allows remote attackers to cause a denial...
ntp_request.c in ntpd in NTP before 4.2.4p8, and 4.2.5, allows remote attackers to cause a denial of service (CPU and bandwidth consumption) by using MODE_PRIVATE to send a spoofed (1) request or (2) response packet that triggers a continuous exchange of MODE_PRIVATE error responses between two NTP daemons.
Exploit likelihood
What each source reports
NVD Score used
ntp_request.c in ntpd in NTP before 4.2.4p8, and 4.2.5, allows remote attackers to cause a denial of service (CPU and bandwidth consumption) by using MODE_PRIVATE to send a spoofed (1) request or (2) response packet that triggers a continuous exchange of MODE_PRIVATE error responses between two NTP daemons.
- Record
CVE-2009-3563- CVSS 2.0
- 6.4 Medium
AV:N/AC:L/Au:N/C:N/I:P/A:P - Updated
- 2026-11-02
CVE List No score
ntp_request.c in ntpd in NTP before 4.2.4p8, and 4.2.5, allows remote attackers to cause a denial of service (CPU and bandwidth consumption) by using MODE_PRIVATE to send a spoofed (1) request or (2) response packet that triggers a continuous exchange of MODE_PRIVATE error responses between two NTP daemons.
- Record
CVE-2009-3563- Updated
- 2026-11-02
EUVDEUVD-2009-3544 No score
ntp_request.c in ntpd in NTP before 4.2.4p8, and 4.2.5, allows remote attackers to cause a denial of service (CPU and bandwidth consumption) by using MODE_PRIVATE to send a spoofed (1) request or (2) response packet that triggers a continuous exchange of MODE_PRIVATE error responses between two NTP daemons.
- Record
EUVD-2009-3544- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-gm22-x89c-4h54 No score
ntp_request.c in ntpd in NTP before 4.2.4p8, and 4.2.5, allows remote attackers to cause a denial...
ntp_request.c in ntpd in NTP before 4.2.4p8, and 4.2.5, allows remote attackers to cause a denial of service (CPU and bandwidth consumption) by using MODE_PRIVATE to send a spoofed (1) request or (2) response packet that triggers a continuous exchange of MODE_PRIVATE error responses between two NTP daemons.
- Record
GHSA-gm22-x89c-4h54- Updated
- 2026-11-02
OSV No score
ntp_request.c in ntpd in NTP before 4.2.4p8, and 4.2.5, allows remote attackers to cause a denial of service (CPU and bandwidth consumption) by using MODE_PRIVATE to send a spoofed (1) request or (2) response packet that triggers a continuous exchange of MODE_PRIVATE error responses between two NTP daemons.
- Record
CVE-2009-3563- Updated
- 2026-11-02
OSVDEBIAN-CVE-2009-3563 No score
ntp_request.c in ntpd in NTP before 4.2.4p8, and 4.2.5, allows remote attackers to cause a denial of service (CPU and bandwidth consumption) by using MODE_PRIVATE to send a spoofed (1) request or (2) response packet that triggers a continuous exchange of MODE_PRIVATE error responses between two NTP daemons.
- Record
DEBIAN-CVE-2009-3563- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
ntpDebian:11 |
before 1:4.2.4p8+dfsg-1 | 1:4.2.4p8+dfsg-1 |
ntpDebian:4.0 |
before 1:4.2.2.p4+dfsg-2etch4, plus listed versions 1:4.2.2.p4+dfsg-21:4.2.2.p4+dfsg-2etch11:4.2.2.p4+dfsg-2etch21:4.2.2.p4+dfsg-2etch3 |
1:4.2.2.p4+dfsg-2etch4 |
ntpDebian:5.0 |
before 1:4.2.4p4+dfsg-8lenny3, plus listed versions 1:4.2.4p4+dfsg-81:4.2.4p4+dfsg-8lenny2 |
1:4.2.4p4+dfsg-8lenny3 |
ntpRed Hat:enterprise_linux:4::as |
before 0:4.2.0.a.20040617-8.el4_8.1 | 0:4.2.0.a.20040617-8.el4_8.1 |
ntp-debuginfoRed Hat:enterprise_linux:4::as |
before 0:4.2.0.a.20040617-8.el4_8.1 | 0:4.2.0.a.20040617-8.el4_8.1 |
ntpRed Hat:enterprise_linux:4::desktop |
before 0:4.2.0.a.20040617-8.el4_8.1 | 0:4.2.0.a.20040617-8.el4_8.1 |
ntp-debuginfoRed Hat:enterprise_linux:4::desktop |
before 0:4.2.0.a.20040617-8.el4_8.1 | 0:4.2.0.a.20040617-8.el4_8.1 |
ntpRed Hat:enterprise_linux:4::es |
before 0:4.2.0.a.20040617-8.el4_8.1 | 0:4.2.0.a.20040617-8.el4_8.1 |
ntp-debuginfoRed Hat:enterprise_linux:4::es |
before 0:4.2.0.a.20040617-8.el4_8.1 | 0:4.2.0.a.20040617-8.el4_8.1 |
ntpRed Hat:enterprise_linux:4::ws |
before 0:4.2.0.a.20040617-8.el4_8.1 | 0:4.2.0.a.20040617-8.el4_8.1 |
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| Package | Affected | Fixed |
|---|---|---|
ntp-debuginfoRed Hat:enterprise_linux:4::ws |
before 0:4.2.0.a.20040617-8.el4_8.1 | 0:4.2.0.a.20040617-8.el4_8.1 |
ntpRed Hat:enterprise_linux:5::client |
before 0:4.2.2p1-9.el5_4.1 | 0:4.2.2p1-9.el5_4.1 |
ntp-debuginfoRed Hat:enterprise_linux:5::client |
before 0:4.2.2p1-9.el5_4.1 | 0:4.2.2p1-9.el5_4.1 |
ntpRed Hat:enterprise_linux:5::server |
before 0:4.2.2p1-9.el5_4.1 | 0:4.2.2p1-9.el5_4.1 |
ntp-debuginfoRed Hat:enterprise_linux:5::server |
before 0:4.2.2p1-9.el5_4.1 | 0:4.2.2p1-9.el5_4.1 |
ntpRed Hat:enterprise_linux:3::as From an advisory covering 2 CVEs |
before 0:4.1.2-6.el3 | 0:4.1.2-6.el3 |
ntp-debuginfoRed Hat:enterprise_linux:3::as From an advisory covering 2 CVEs |
before 0:4.1.2-6.el3 | 0:4.1.2-6.el3 |
ntpRed Hat:enterprise_linux:3::desktop From an advisory covering 2 CVEs |
before 0:4.1.2-6.el3 | 0:4.1.2-6.el3 |
ntp-debuginfoRed Hat:enterprise_linux:3::desktop From an advisory covering 2 CVEs |
before 0:4.1.2-6.el3 | 0:4.1.2-6.el3 |
ntpRed Hat:enterprise_linux:3::es From an advisory covering 2 CVEs |
before 0:4.1.2-6.el3 | 0:4.1.2-6.el3 |
ntp-debuginfoRed Hat:enterprise_linux:3::es From an advisory covering 2 CVEs |
before 0:4.1.2-6.el3 | 0:4.1.2-6.el3 |
ntpRed Hat:enterprise_linux:3::ws From an advisory covering 2 CVEs |
before 0:4.1.2-6.el3 | 0:4.1.2-6.el3 |
ntp-debuginfoRed Hat:enterprise_linux:3::ws From an advisory covering 2 CVEs |
before 0:4.1.2-6.el3 | 0:4.1.2-6.el3 |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| Metasploit | NTP.org ntpd Reserved Mode Denial of Service | 2009-10-04 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, Metasploit, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2009-3563 is a medium vulnerability (CVSS 6.4) in Ntp, published December 8, 2009. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 32.1%, the 98th percentile. Fixed in ntp 1:4.2.4p8+dfsg-1.
References
kb.cert.org/vuls/id/568372
secunia.com/advisories/38832
kb.juniper.net/InfoCenter/index?page=content&id=JSA10673
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11225
support.avaya.com/css/P8/documents/100071808
Show 49 moreShow less
lists.vmware.com/pipermail/security-announce/2010/000082.html
redhat.com/archives/fedora-package-announce/2009-December/msg00809.html
bugzilla.redhat.com/show_bug.cgi?id=531213
support.ntp.org/bin/view/Main/SecurityNotice
securityfocus.com/bid/37255
marc.info?l=bugtraq&m=136482797910018&w=2
www-01.ibm.com/support/docview.wss?uid=isg1IZ71047
vupen.com/english/advisories/2010/0993
debian.org/security/2009/dsa-1948
bugs.debian.org/cgi-bin/bugreport.cgi?bug=560074
aix.software.ibm.com/aix/efixes/security/xntpd_advisory.asc
sunsolve.sun.com/search/document.do?assetkey=1-77-1021781.1-1
security-tracker.debian.org/tracker/CVE-2009-3563
securitytracker.com/id?1023298
rhn.redhat.com/errata/RHSA-2009-1651.html
lists.ntp.org/pipermail/announce/2009-December/000086.html
nvd.nist.gov/vuln/detail/CVE-2009-3563
github.com/advisories/GHSA-gm22-x89c-4h54
access.redhat.com/errata/RHSA-2009:1648
security.access.redhat.com/data/csaf/v2/advisories/2009/rhsa-2009_1648.json
cve.org/CVERecord?id=CVE-2009-3563