ASP.NET Core SignalR and Visual Studio Information Disclosure Vulnerability
CVE-2023-35391
Security Vulnerability
Released: Aug 8, 2023
Last updated: Oct 17, 2023
- Assigning CNA
- Microsoft
- CVE.org link
- CVE-2023-35391
- Impact
- Information Disclosure
- Max Severity
- Important
- CVSS Source
- Microsoft
- Vector String
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:C
- Metrics
- CVSS:3.1 6.2 / 5.6Base score metrics: 6.2 / Temporal score metrics: 5.6
Metric
Value
Base score metrics(8)
Attack Vector
This metric reflects the context by which vulnerability exploitation is possible. The Base Score increases the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable component.
Local
The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document)
Attack Complexity
This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability. Such conditions may require the collection of more information about the target or computational exceptions. The assessment of this metric excludes any requirements for user interaction in order to exploit the vulnerability. If a specific configuration is required for an attack to succeed, the Base metrics should be scored assuming the vulnerable component is in that configuration.
Low
Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against 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 to carry out an attack.
User Interaction
This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise the vulnerable component. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
None
The vulnerable system can be exploited without any interaction from any user.
Scope
Does a successful attack impact a component other than the vulnerable component? If so, the Base Score increases and the Confidentiality, Integrity and Authentication metrics should be scored relative to the impacted component.
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.
Confidentiality
This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
High
There is 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.
Integrity
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
This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. It refers to the loss of availability of the impacted component itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of an impacted component.
None
There is no impact to availability within the impacted component.
Temporal score metrics(3)
Exploit Code Maturity
This metric measures the likelihood of the vulnerability being attacked, and is typically based on the current state of exploit techniques, public availability of exploit code, or active, 'in-the-wild' exploitation.
Proof-of-Concept
Proof-of-concept exploit code is available, or an attack demonstration is not practical for most systems. The code or technique is not functional in all situations and may require substantial modification by a skilled attacker.
Remediation Level
The Remediation Level of a vulnerability is an important factor for prioritization. The typical vulnerability is unpatched when initially published. Workarounds or hotfixes may offer interim remediation until an official patch or upgrade is issued. Each of these respective stages adjusts the temporal score downwards, reflecting the decreasing urgency as remediation becomes final.
Official Fix
A complete vendor solution is available. Either the vendor has issued an official patch, or an upgrade is available.
Report Confidence
This metric measures the degree of confidence in the existence of the vulnerability and the credibility of the known technical details. Sometimes only the existence of vulnerabilities are publicized, but without specific details. For example, an impact may be recognized as undesirable, but the root cause may not be known. The vulnerability may later be corroborated by research which suggests where the vulnerability may lie, though the research may not be certain. Finally, a vulnerability may be confirmed through acknowledgement by the author or vendor of the affected technology. The urgency of a vulnerability is higher when a vulnerability is known to exist with certainty. This metric also suggests the level of technical knowledge available to would-be attackers.
Confirmed
Detailed reports exist, or functional reproduction is possible (functional exploits may provide this). Source code is available to independently verify the assertions of the research, or the author or vendor of the affected code has confirmed the presence of the vulnerability.
Please see Common Vulnerability Scoring System for more information on the definition of these metrics.
Exploitability
The following table provides an exploitability assessment for this vulnerability at the time of original publication.
- Publicly disclosed
- No
- Exploited
- No
- Exploitability assessment
- Exploitation Less Likely
FAQ
What type of information could be disclosed by this vulnerability?
This vulnerability makes it possible to listen to any group or user with a specially crafted group/username. By exploiting this vulnerability, the attacker can now receive messages for group(s) that they are unauthorized to view.
According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is information disclosure?
The attack itself is carried out locally. For example, when the score indicates that the Attack Vector is Local (AV:L) and User Interaction is Required (UI:R), this could describe an exploit in which an attacker, through social engineering, convinces a victim to download and run a malicious application. This could lead to a local attack on the user's device which could leak data.
Acknowledgements
- Brennan Conroy
Security Updates
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle.
Release date Descending
Product
Platform
Impact
Max Severity
Article
Download
Build Number
Aug 8, 2023
Microsoft Visual Studio 2022 version 17.6
-
Information Disclosure
Important
- 17.6.6
Aug 8, 2023
Microsoft Visual Studio 2022 version 17.4
-
Information Disclosure
Important
- 17.4.10
Aug 8, 2023
Microsoft Visual Studio 2022 version 17.2
-
Information Disclosure
Important
- 17.2.18
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Disclaimer
The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
Revisions
version
revisionDate
description
1.1
Oct 17, 2023
Updated one or more CVSS scores for the affected products and added an FAQ explaining the vector string settings. This is an informational change only.
1.0
Aug 8, 2023
Information published.
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