CVE-2021-25217 : 상세 정보

CVE-2021-25217

7.4
/
높음
0.45%V4
2021-05-26
22h10 +00:00
Overflow
Adjacent
2024-09-16
22h08 +00:00
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특정 CVE의 변경 사항에 대한 정보를 받아보세요.
알림 관리

CVE 설명

A buffer overrun in lease file parsing code can be used to exploit a common vulnerability shared by dhcpd and dhclient

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.

CVE 해결 방법

Upgrade to the patched release most closely related to your current version of ISC DHCP: ISC DHCP 4.1-ESV-R16-P1 ISC DHCP 4.4.2-P1

CVE 정보

관련 약점

CWE-ID 약점 이름 출처
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.

메트릭

메트릭 점수 심각도 CVSS 벡터 출처
V3.1 7.4 HIGH CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Adjacent

The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).

Attack Complexity

This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.

User Interaction

This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope.

Scope

Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs.

Changed

An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.

Base: Impact Metrics

The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

None

There is no loss of confidentiality within the impacted component.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

None

There is no loss of integrity within the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence in the description of a vulnerability.

Environmental Metrics

These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.

V2 3.3 AV:A/AC:L/Au:N/C:N/I:N/A:P nvd@nist.gov

EPSS

EPSS는 취약점이 악용될 가능성을 예측하는 점수 모델입니다.

EPSS 점수

EPSS 모델은 0과 1(0~100%) 사이의 확률 점수를 생성합니다. 점수가 높을수록 취약점이 악용될 가능성이 높습니다.

EPSS 백분위수

백분위수는 EPSS 점수에 따라 CVE의 순위를 매기는 데 사용됩니다. 예를 들어 EPSS 점수 기준 95번째 백분위수의 CVE는 다른 CVE의 95%보다 악용될 가능성이 높습니다.

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Isc>>Dhcp >> Version 부터 (포함) 4.4.0 까지 (포함) 4.4.2

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

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Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

Isc>>Dhcp >> Version 4.1-esv

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Fedoraproject>>Fedora >> Version 33

Fedoraproject>>Fedora >> Version 34

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Debian>>Debian_linux >> Version 9.0

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Siemens>>Ruggedcom_rox_rx1500_firmware >> Version 부터 (포함) 2.3.0 까지 (미포함) 2.15.0

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Siemens>>Ruggedcom_rox_rx1501_firmware >> Version 부터 (포함) 2.3.0 까지 (미포함) 2.15.0

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Siemens>>Ruggedcom_rox_rx1510_firmware >> Version 부터 (포함) 2.3.0 까지 (미포함) 2.15.0

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Siemens>>Ruggedcom_rox_rx1512_firmware >> Version 부터 (포함) 2.3.0 까지 (미포함) 2.15.0

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Siemens>>Ruggedcom_rox_rx1524_firmware >> Version 까지 (미포함) 2.15.0

Siemens>>Ruggedcom_rox_rx1524 >> Version -

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참고 자료

https://kb.isc.org/docs/cve-2021-25217
Tags : Exploit, Vendor Advisory