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CVE-2020-8835 : Detail

CVE-2020-8835

7.8
/
HIGH
Overflow
0.09%V3
Local
2020-03-29 22:00 +00:00
2021-07-20 12:06 +00:00
CVE.org
NVD

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Descriptions

Linux kernel bpf verifier vulnerability

In the Linux kernel 5.5.0 and newer, the bpf verifier (kernel/bpf/verifier.c) did not properly restrict the register bounds for 32-bit operations, leading to out-of-bounds reads and writes in kernel memory. The vulnerability also affects the Linux 5.4 stable series, starting with v5.4.7, as the introducing commit was backported to that branch. This vulnerability was fixed in 5.6.1, 5.5.14, and 5.4.29. (issue is aka ZDI-CAN-10780)

Solutions

Revert commit 581738a681b6 ("bpf: Provide better register bounds after jmp32 instructions").

Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-125 Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
CWE-787 Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended buffer.

Metrics

Metric Score Severity CVSS Vector Source
V3.1 7.8 HIGH CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/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.

Local

The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities.

Attack Complexity

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

High

successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected.

Privileges Required

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

Low

The attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.

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.

High

There is a total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

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

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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.
V3.1 7.8 HIGH CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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.

Local

The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities.

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.

Low

The attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.

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.

Unchanged

An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.

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.

High

There is a total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

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

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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.

 nvd@nist.gov
V2 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C nvd@nist.gov

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
EPSS First.org

Products Mentioned

Configuraton 0

Linux>>Linux_kernel >> Version From (including) 5.4.7 To (excluding) 5.4.29

Linux>>Linux_kernel >> Version From (including) 5.5.0 To (excluding) 5.5.14

Linux>>Linux_kernel >> Version From (including) 5.6 To (excluding) 5.6.1

Configuraton 0

Fedoraproject>>Fedora >> Version 30

Fedoraproject>>Fedora >> Version 31

Fedoraproject>>Fedora >> Version 32

Configuraton 0

Canonical>>Ubuntu_linux >> Version 18.04

Canonical>>Ubuntu_linux >> Version 19.10

Configuraton 0

Netapp>>Cloud_backup >> Version -

Netapp>>Hci_management_node >> Version -

Netapp>>Solidfire >> Version -

Netapp>>Steelstore_cloud_integrated_storage >> Version -

Configuraton 0

Netapp>>A700s_firmware >> Version -

Netapp>>A700s >> Version -

Configuraton 0

Netapp>>8300_firmware >> Version -

Netapp>>8300 >> Version -

Configuraton 0

Netapp>>8700_firmware >> Version -

Netapp>>8700 >> Version -

Configuraton 0

Netapp>>A400_firmware >> Version -

Netapp>>A400 >> Version -

Configuraton 0

Netapp>>A320_firmware >> Version -

Netapp>>A320 >> Version -

Configuraton 0

Netapp>>C190_firmware >> Version -

Netapp>>C190 >> Version -

Configuraton 0

Netapp>>A220_firmware >> Version -

Netapp>>A220 >> Version -

Configuraton 0

Netapp>>Fas2720_firmware >> Version -

Netapp>>Fas2720 >> Version -

Configuraton 0

Netapp>>Fas2750_firmware >> Version -

Netapp>>Fas2750 >> Version -

Configuraton 0

Netapp>>A800_firmware >> Version -

Netapp>>A800 >> Version -

Configuraton 0

Netapp>>H300s_firmware >> Version -

Netapp>>H300s >> Version -

Configuraton 0

Netapp>>H500s_firmware >> Version -

Netapp>>H500s >> Version -

Configuraton 0

Netapp>>H700s_firmware >> Version -

Netapp>>H700s >> Version -

Configuraton 0

Netapp>>H300e_firmware >> Version -

Netapp>>H300e >> Version -

Configuraton 0

Netapp>>H500e_firmware >> Version -

Netapp>>H500e >> Version -

Configuraton 0

Netapp>>H700e_firmware >> Version -

Netapp>>H700e >> Version -

Configuraton 0

Netapp>>H410s_firmware >> Version -

Netapp>>H410s >> Version -

Configuraton 0

Netapp>>H610c_firmware >> Version -

Netapp>>H610c >> Version -

Configuraton 0

Netapp>>H610s_firmware >> Version -

Netapp>>H610s >> Version -

Configuraton 0

Netapp>>H615c_firmware >> Version -

Netapp>>H615c >> Version -

References

https://usn.ubuntu.com/4313-1/
Tags : vendor-advisory, x_refsource_UBUNTU
http://www.openwall.com/lists/oss-security/2021/07/20/1
Tags : mailing-list, x_refsource_MLIST

More information
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