high
7.5
CWE
190
Advisory Published
CVE Published
Updated

CVE-2018-5733: A malicious client can overflow a reference counter in ISC dhcpd

First published: Wed Feb 28 2018(Updated: )

A malicious client which is allowed to send very large amounts of traffic (billions of packets) to a DHCP server can eventually overflow a 32-bit reference counter, potentially causing dhcpd to crash. Versions of DHCP affected: 4.1.0 -> 4.1-ESV-R15, 4.2.0 -> 4.2.8, 4.3.0 -> 4.3.6, 4.4.0

Credit: security-officer@isc.org

Affected SoftwareAffected VersionHow to fix
redhat/dhcp<4.1
4.1
redhat/dhcp<4.3.6
4.3.6
redhat/dhcp<4.4.1
4.4.1
debian/isc-dhcp
4.4.1-2.3+deb11u2
4.4.1-2.3+deb11u1
4.4.3-P1-2
4.4.3-P1-5
ISC DHCP>=4.2.0<=4.2.8
ISC DHCP>=4.3.0<=4.3.6
ISC DHCP=4.1-esv
ISC DHCP=4.1-esv-r1
ISC DHCP=4.1-esv-r10
ISC DHCP=4.1-esv-r10_b1
ISC DHCP=4.1-esv-r10_rc1
ISC DHCP=4.1-esv-r11
ISC DHCP=4.1-esv-r11_b1
ISC DHCP=4.1-esv-r11_rc1
ISC DHCP=4.1-esv-r11_rc2
ISC DHCP=4.1-esv-r12
ISC DHCP=4.1-esv-r12_b1
ISC DHCP=4.1-esv-r12_p1
ISC DHCP=4.1-esv-r13
ISC DHCP=4.1-esv-r13_b1
ISC DHCP=4.1-esv-r14
ISC DHCP=4.1-esv-r14_b1
ISC DHCP=4.1-esv-r15
ISC DHCP=4.1-esv-r2
ISC DHCP=4.1-esv-r3
ISC DHCP=4.1-esv-r3_b1
ISC DHCP=4.1-esv-r4
ISC DHCP=4.1-esv-r5
ISC DHCP=4.1-esv-r5_b1
ISC DHCP=4.1-esv-r5_rc1
ISC DHCP=4.1-esv-r5_rc2
ISC DHCP=4.1-esv-r6
ISC DHCP=4.1-esv-r7
ISC DHCP=4.1-esv-r8
ISC DHCP=4.1-esv-r8_b1
ISC DHCP=4.1-esv-r8_rc1
ISC DHCP=4.1-esv-r9
ISC DHCP=4.1-esv-r9_b1
ISC DHCP=4.1-esv-r9_rc1
ISC DHCP=4.1-esv-rc1
ISC DHCP=4.1.0
ISC DHCP=4.4.0
Red Hat Enterprise Linux Desktop=6.0
Red Hat Enterprise Linux Desktop=7.0
Red Hat Enterprise Linux Server=6.0
Red Hat Enterprise Linux Server=7.0
Red Hat Enterprise Linux Server=7.4
Red Hat Enterprise Linux Server=7.6
Red Hat Enterprise Linux Server=7.4
Red Hat Enterprise Linux Server=7.5
Red Hat Enterprise Linux Server=7.6
Red Hat Enterprise Linux Workstation=6.0
Red Hat Enterprise Linux Workstation=7.0
Ubuntu=14.04
Ubuntu=16.04
Ubuntu=17.10
Debian Linux=7.0
Debian Linux=8.0
Debian Linux=9.0

Remedy

Upgrade to the patched release most closely related to your current version of DHCP. DHCP 4.1-ESV-R15-P1 DHCP 4.3.6-P1 DHCP 4.4.1

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2018-5733?

    CVE-2018-5733 is considered a high severity vulnerability as it can lead to the crash of a DHCP server.

  • How do I fix CVE-2018-5733?

    To fix CVE-2018-5733, upgrade the DHCP server software to versions 4.1.1 or later, or apply the necessary patches provided by your distribution.

  • What software is affected by CVE-2018-5733?

    CVE-2018-5733 affects ISC DHCP versions 4.1.0 through 4.2.8 as well as specific versions up to 4.3.6 and 4.4.1.

  • What could an attacker do with CVE-2018-5733?

    An attacker could exploit CVE-2018-5733 by sending a large volume of traffic to overwhelm the DHCP server, potentially leading to service disruptions.

  • Is CVE-2018-5733 a remote code execution vulnerability?

    No, CVE-2018-5733 does not involve remote code execution; it can cause a denial of service by crashing the DHCP service instead.

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