Strix
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CVE-2021-25217

HIGHCVSS 7.4/10EPSS 6.12%

Last modified

CVE-2021-25217 is a high-severity vulnerability rated 7.4/10 on the CVSS scale. In ISC DHCP 4.1-ESV-R1 -> 4.1-ESV-R16, ISC DHCP 4.4.0 -> 4.4.2 (Other branches of ISC DHCP (i.e., releases in the 4.0.x series or lower and releases in the 4.3.x series) are beyond their End-of-Life (EOL) and no longer supported by ISC. From inspection it is clear that the defect is also present in releases from those series, but they have not been officially tested for the vulnerability), The outcome of encountering the defect while reading a lease that will trigger it varies, according to: the component being affected (i.e., dhclient or dhcpd) whether the package was built as a 32-bit or 64-bit binary whether the compiler flag -fstack-protection-strong was used when compiling In dhclient, ISC has not successfully reproduced the error on a 64-bit system. EPSS estimates a 6.12% chance of exploitation in the next 30 days.

Description

In ISC DHCP 4.1-ESV-R1 -> 4.1-ESV-R16, ISC DHCP 4.4.0 -> 4.4.2 (Other branches of ISC DHCP (i.e., releases in the 4.0.x series or lower and releases in the 4.3.x series) are beyond their End-of-Life (EOL) and no longer supported by ISC. From inspection it is clear that the defect is also present in releases from those series, but they have not been officially tested for the vulnerability), The outcome of encountering the defect while reading a lease that will trigger it varies, according to: the component being affected (i.e., dhclient or dhcpd) whether the package was built as a 32-bit or 64-bit binary whether the compiler flag -fstack-protection-strong was used when compiling In dhclient, ISC has not successfully reproduced the error on a 64-bit system. However, on a 32-bit system it is possible to cause dhclient to crash when reading an improper lease, which could cause network connectivity problems for an affected system due to the absence of a running DHCP client process. In dhcpd, when run in DHCPv4 or DHCPv6 mode: if the dhcpd server binary was built for a 32-bit architecture AND the -fstack-protection-strong flag was specified to the compiler, dhcpd may exit while parsing a lease file containing an objectionable lease, resulting in lack of service to clients. Additionally, the offending lease and the lease immediately following it in the lease database may be improperly deleted. if the dhcpd server binary was built for a 64-bit architecture OR if the -fstack-protection-strong compiler flag was NOT specified, the crash will not occur, but it is possible for the offending lease and the lease which immediately followed it to be improperly deleted.

Metrics

CVSS 3.1
7.4/10

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

EPSS Probability
6.12%

92.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
IscDhcp>= 4.4.0, <= 4.4.2—
IscDhcp4.1-esvR1
FedoraprojectFedora33—
FedoraprojectFedora34—
DebianDebian Linux9.0—
SiemensRuggedcom Rox Rx1400 Firmware< 2.15.0—
SiemensRuggedcom Rox Rx1500 Firmware>= 2.3.0, < 2.15.0—
SiemensRuggedcom Rox Rx1501 Firmware>= 2.3.0, < 2.15.0—
SiemensRuggedcom Rox Rx1510 Firmware>= 2.3.0, < 2.15.0—
SiemensRuggedcom Rox Rx1511 Firmware>= 2.3.0, < 2.15.0—
SiemensRuggedcom Rox Rx1512 Firmware>= 2.3.0, < 2.15.0—
SiemensRuggedcom Rox Rx1524 Firmware< 2.15.0—
SiemensRuggedcom Rox Rx1536 Firmware< 2.15.0—
SiemensRuggedcom Rox Rx5000 Firmware>= 2.3.0, < 2.15.0—
SiemensRuggedcom Rox Mx5000 Firmware>= 2.3.0, < 2.15.0—
NetappOntap Select Deploy Administration UtilityAll versions—
NetappSolidfire \& Hci Management NodeAll versions—
SiemensSinec Ins< 1.0—
SiemensSinec Ins1.0—

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-25217?
In ISC DHCP 4.1-ESV-R1 -> 4.1-ESV-R16, ISC DHCP 4.4.0 -> 4.4.2 (Other branches of ISC DHCP (i.e., releases in the 4.0.x series or lower and releases in the 4.3.x series) are beyond their End-of-Life (EOL) and no longer supported by ISC. From inspection it is clear that the defect is also present in releases from those series, but they have not been officially tested for the vulnerability), The outcome of encountering the defect while reading a lease that will trigger it varies, according to: the component being affected (i.e., dhclient or dhcpd) whether the package was built as a 32-bit or 64-bit binary whether the compiler flag -fstack-protection-strong was used when compiling In dhclient, ISC has not successfully reproduced the error on a 64-bit system. However, on a 32-bit system it is possible to cause dhclient to crash when reading an improper lease, which could cause network connectivity problems for an affected system due to the absence of a running DHCP client process. In dhcpd, when run in DHCPv4 or DHCPv6 mode: if the dhcpd server binary was built for a 32-bit architecture AND the -fstack-protection-strong flag was specified to the compiler, dhcpd may exit while parsing a lease file containing an objectionable lease, resulting in lack of service to clients. Additionally, the offending lease and the lease immediately following it in the lease database may be improperly deleted. if the dhcpd server binary was built for a 64-bit architecture OR if the -fstack-protection-strong compiler flag was NOT specified, the crash will not occur, but it is possible for the offending lease and the lease which immediately followed it to be improperly deleted.
How severe is CVE-2021-25217?
CVE-2021-25217 has a CVSS score of 7.4/10 (HIGH severity). The EPSS model estimates a 6.12% probability of exploitation in the next 30 days.
How do I fix CVE-2021-25217?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-25217?

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Source: NVD / NIST