Executive Summary
Summary | |
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Title | Microsoft SMBv3 compression remote code execution vulnerability |
Informations | |||
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Name | VU#872016 | First vendor Publication | 2020-03-23 |
Vendor | VU-CERT | Last vendor Modification | 2020-06-04 |
Severity (Vendor) | N/A | Revision | M |
Security-Database Scoring CVSS v3
Cvss vector : CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H | |||
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Overall CVSS Score | 10 | ||
Base Score | 10 | Environmental Score | 10 |
impact SubScore | 6 | Temporal Score | 10 |
Exploitabality Sub Score | 3.9 | ||
Attack Vector | Network | Attack Complexity | Low |
Privileges Required | None | User Interaction | None |
Scope | Changed | Confidentiality Impact | High |
Integrity Impact | High | Availability Impact | High |
Calculate full CVSS 3.0 Vectors scores |
Security-Database Scoring CVSS v2
Cvss vector : (AV:N/AC:L/Au:N/C:P/I:P/A:P) | |||
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Cvss Base Score | 7.5 | Attack Range | Network |
Cvss Impact Score | 6.4 | Attack Complexity | Low |
Cvss Expoit Score | 10 | Authentication | None Required |
Calculate full CVSS 2.0 Vectors scores |
Detail
OverviewMicrosoft SMBv3 contains a vulnerability in the handling of compression, which may allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system. This vulnerability is being referred to as "SMBGhost and CoronaBlue." DescriptionMicrosoft Server Message Block 3.1.1 (SMBv3) contains a vulnerability in the way that it handles connections that use compression. This vulnerability may allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system. It has been reported that this vulnerability is "wormable." ImpactBy connecting to a vulnerable Windows machine using SMBv3, or by causing a vulnerable Windows system to initiate a client connection to a SMBv3 server, a remote, unauthenticated attacker may be able to execute arbitrary code with SYSTEM privileges on a vulnerable system. SolutionApply an update This issue has been addressed in the Microsoft update for CVE-2020-0796. Please also consider the following workarounds: Disable SMBv3 compression You can disable compression to block unauthenticated attackers from exploiting the vulnerability against an SMBv3 Server with the PowerShell command below. Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters" DisableCompression -Type DWORD -Value 1 -Force Notes: 1. No reboot is needed after making the change. 2. This workaround does not prevent exploitation of SMB clients. You can disable the workaround with the PowerShell command below. Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters" DisableCompression -Type DWORD -Value 0 -Force Block inbound and outbound SMB Consider blocking outbound SMB connections (TCP port 445 for SMBv3) from the local network to the WAN. Also ensure that SMB connections from the internet are not allowed to connect inbound to an enterprise LAN. AcknowledgementsThis document was written by Will Dormann. |
Original Source
Url : https://kb.cert.org/vuls/id/872016 |
CWE : Common Weakness Enumeration
% | Id | Name |
---|---|---|
100 % | CWE-119 | Failure to Constrain Operations within the Bounds of a Memory Buffer |
CPE : Common Platform Enumeration
Type | Description | Count |
---|---|---|
Os | 1 | |
Os | 1 | |
Os | 1 | |
Os | 1 |
Snort® IPS/IDS
Date | Description |
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2020-04-14 | Microsoft Windows SMB srv2.sys remote code execution attempt RuleID : 53448 - Revision : 1 - Type : OS-WINDOWS |
2020-04-14 | Microsoft Windows SMB srv2.sys remote code execution attempt RuleID : 53447 - Revision : 1 - Type : OS-WINDOWS |
2020-04-14 | Microsoft Windows SMB srv2.sys remote code execution attempt RuleID : 53428 - Revision : 3 - Type : OS-WINDOWS |
2020-04-14 | Microsoft Windows SMB srv2.sys remote code execution attempt RuleID : 53427 - Revision : 3 - Type : OS-WINDOWS |
2020-04-14 | Microsoft Windows SMB srv2.sys remote code execution attempt RuleID : 53426 - Revision : 3 - Type : OS-WINDOWS |
2020-04-14 | Microsoft Windows SMB srv2.sys remote code execution attempt RuleID : 53425 - Revision : 3 - Type : OS-WINDOWS |
Alert History
Date | Informations |
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2020-06-12 21:17:42 |
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2020-06-05 00:17:31 |
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2020-05-23 13:15:40 |
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