ntp-keygen in ntp 4.2.8px before 4.2.8p2-RC2 and 4.3.x before 4.3.12 does not generate MD5 keys with sufficient entropy on big endian machin
ntp-keygen in ntp 4.2.8px before 4.2.8p2-RC2 and 4.3.x before 4.3.12 does not generate MD5 keys with sufficient entropy on big endian machines when the lowest order byte of the temp variable is between 0x20 and 0x7f and not #, which might allow remote attackers to obtain the value of generated MD5 keys via a brute force attack with the 93 possible keys.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for help- Published
- Aug 9, 2017
- Updated
- Jun 16, 2026
- EPSS
- 5.3% · 92th percentile
- CWE
- CWE-331
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Report tools
Action score
32
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 2 / 30 · 5.3%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| ntp | ntp | cpe:2.3:a:ntp:ntp |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| opensuse | suse linux enterprise server | cpe:2.3:o:opensuse:suse_linux_enterprise_server |
| opensuse project | suse linux enterprise desktop | cpe:2.3:o:opensuse_project:suse_linux_enterprise_desktop |
| suse | suse linux enterprise server | cpe:2.3:o:suse:suse_linux_enterprise_server |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| redhat | enterprise linux desktop | cpe:2.3:o:redhat:enterprise_linux_desktop |
| redhat | enterprise linux for ibm z systems | cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems |
| redhat | enterprise linux for power big endian | cpe:2.3:o:redhat:enterprise_linux_for_power_big_endian |
| redhat | enterprise linux for scientific computing | cpe:2.3:o:redhat:enterprise_linux_for_scientific_computing |
| redhat | enterprise linux server | cpe:2.3:o:redhat:enterprise_linux_server |
| redhat | enterprise linux server from rhui 6 | cpe:2.3:o:redhat:enterprise_linux_server_from_rhui_6 |
and 1 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux7.0
- debian debian linux8.0
- fedoraproject fedora21
- ntp ntp4.2.8
- ntp ntp4.3.0
- ntp ntp4.3.1
- ntp ntp4.3.10
- ntp ntp4.3.11
- ntp ntp4.3.2
- ntp ntp4.3.3
- ntp ntp4.3.4
- ntp ntp4.3.5
- ntp ntp4.3.6
- ntp ntp4.3.7
- ntp ntp4.3.8
- ntp ntp4.3.9
- opensuse suse linux enterprise server11.0
- opensuse project suse linux enterprise desktop11.0
- redhat enterprise linux desktop6.0
- redhat enterprise linux for ibm z systems6.0
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:11 | ntp | before 1:4.2.6.p5+dfsg-7 | 1:4.2.6.p5+dfsg-7 |
| Debian:6.0 | ntp | before 1:4.2.6.p2+dfsg-1+deb6u3 | 1:4.2.6.p2+dfsg-1+deb6u3 |
| Debian:7 | ntp | before 1:4.2.6.p5+dfsg-2+deb7u4 | 1:4.2.6.p5+dfsg-2+deb7u4 |
| Red Hat:enterprise_linux:6::client | ntp | before 0:4.2.6p5-5.el6 | 0:4.2.6p5-5.el6 |
| Red Hat:enterprise_linux:6::client | ntp-debuginfo | before 0:4.2.6p5-5.el6 | 0:4.2.6p5-5.el6 |
| Red Hat:enterprise_linux:6::client | ntp-doc | before 0:4.2.6p5-5.el6 | 0:4.2.6p5-5.el6 |
| Red Hat:enterprise_linux:6::client | ntp-perl | before 0:4.2.6p5-5.el6 | 0:4.2.6p5-5.el6 |
| Red Hat:enterprise_linux:6::client | ntpdate | before 0:4.2.6p5-5.el6 | 0:4.2.6p5-5.el6 |
| Red Hat:enterprise_linux:7::client | ntp | before 0:4.2.6p5-22.el7 | 0:4.2.6p5-22.el7 |
| Red Hat:enterprise_linux:7::client | ntp-debuginfo | before 0:4.2.6p5-22.el7 | 0:4.2.6p5-22.el7 |
| Red Hat:enterprise_linux:7::client | ntp-doc | before 0:4.2.6p5-22.el7 | 0:4.2.6p5-22.el7 |
| Red Hat:enterprise_linux:7::client | ntp-perl | before 0:4.2.6p5-22.el7 | 0:4.2.6p5-22.el7 |
| Red Hat:enterprise_linux:7::client | ntpdate | before 0:4.2.6p5-22.el7 | 0:4.2.6p5-22.el7 |
| Red Hat:enterprise_linux:7::client | sntp | before 0:4.2.6p5-22.el7 | 0:4.2.6p5-22.el7 |
| SUSE:Linux Enterprise Desktop 12 | ntp | before 4.2.6p5-44.1 | 4.2.6p5-44.1 |
Same product
ntp: all recordsOther highest-scoring records for the same primary product.
- CVE-2015-7871Crypto-NAK packets in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to bypass authentication.64This week
- CVE-2014-9295Multiple stack-based buffer overflows in ntpd in NTP before 4.2.8 allow remote attackers to execute arbitrary code via a crafted packet, rel54Plan
- CVE-2013-5211The monlist feature in ntp_request.c in ntpd in NTP before 4.2.7p26 allows remote attackers to cause a denial of service (traffic amplificat49Plan
- CVE-2018-12327Stack-based buffer overflow in ntpq and ntpdc of NTP version 4.2.8p11 allows an attacker to achieve code execution or escalate to higher pri47Plan
- CVE-2016-7434The read_mru_list function in NTP before 4.2.8p9 allows remote attackers to cause a denial of service (crash) via a crafted mrulist query.46Plan
- CVE-2015-7853The datalen parameter in the refclock driver in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to execute arbitra43Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:ntp | 1:4.2.6.p5+dfsg-7 · Debian:11 | Package registry (OSV) |
| red hat:ntp | 0:4.2.6p5-5.el6 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:ntp-debuginfo | 0:4.2.6p5-5.el6 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:ntp-doc | 0:4.2.6p5-5.el6 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:ntp-perl | 0:4.2.6p5-5.el6 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:ntpdate | 0:4.2.6p5-5.el6 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:sntp | 0:4.2.6p5-22.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| suse:ntp | 4.2.6p5-44.1 · SUSE:Linux Enterprise Desktop 12 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-331 · Insufficient EntropyCVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- bk1.ntp.org/ntp-stable/?PAGE=patch&REV=55199296N2gFqH1Hm5GOnhrk9Ypygg
- lists.fedoraproject.org/pipermail/package-announce/2015-April/156248.html
- lists.opensuse.org/opensuse-security-announce/2015-07/msg00000.html
- rhn.redhat.com/errata/RHSA-2015-1459.html
- rhn.redhat.com/errata/RHSA-2015-2231.html
- www.debian.org/security/2015/dsa-3223
- www.debian.org/security/2015/dsa-3388
- www.openwall.com/lists/oss-security/2015/04/23/14
- www.oracle.com/technetwork/topics/security/bulletinapr2015-2511959.html
- www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
- www.securityfocus.com/bid/74045
- bugs.ntp.org/show_bug.cgi?id=2797
- bugzilla.redhat.com/show_bug.cgi?id=1210324
- support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03886en_us
Vendor advisories and official records. Exploit/PoC links are deliberately left out.