Net-NTLMv2 hash leak in Microsoft Outlook
| Risk | Critical |
| Patch available | YES |
| Number of vulnerabilities | 1 |
| CVE-ID | CVE-2023-23397 |
| CWE-ID | CWE-200 |
| Exploitation vector | Network |
| Public exploit | This vulnerability is being exploited in the wild. |
| Vulnerable software Subscribe |
Microsoft Outlook Client/Desktop applications / Office applications Microsoft Office Client/Desktop applications / Office applications |
| Vendor | Microsoft |
Security Bulletin
This security bulletin contains one critical risk vulnerability.
1) Information disclosure
EUVDB-ID: #VU73511
Risk: Critical
CVSSv3.1:
CVE-ID: CVE-2023-23397
CWE-ID:
Exploit availability:
DescriptionThe vulnerability allows a remote attacker to compromise the affected system.
The vulnerability exists due to the application leaks the Net-NTLMv2 hash. A remote attacker can send a specially crafted email to the victim and obtain the Net-NTLMv2 hash of the Windows account. The victim does not need to open the email, as the vulnerability is triggered automatically when it is retrieved and processed by the email server, e.g. before the email is viewed in the preview pane.
The obtained NTLMv2 hash can be used in the NTLM Relay attack against another service to authenticate as the user.
Note, the vulnerability is being actively exploited in the wild.
Install updates from vendor's website.
Vulnerable software versionsMicrosoft Outlook: 2013 - 2021
Microsoft Office: 365 - 2021
Fixed software versionsCPE2.3 External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-23397
http://www.mdsec.co.uk/2023/03/exploiting-cve-2023-23397-microsoft-outlook-elevation-of-privilege-vulnerability/
Q & A
Can this vulnerability be exploited remotely?
How the attacker can exploit this vulnerability?
Is there known malware, which exploits this vulnerability?
