Multiple vulnerabilities in Microsoft Exchange Server
| Risk | Medium |
| Patch available | YES |
| Number of vulnerabilities | 2 |
| CVE-ID | CVE-2021-24085 CVE-2021-1730 |
| CWE-ID | CWE-352 CWE-451 |
| Exploitation vector | Network |
| Public exploit | Public exploit code for vulnerability #1 is available. |
| Vulnerable software Subscribe |
Microsoft Exchange Server Server applications / Mail servers |
| Vendor | Microsoft |
Security Bulletin
This security bulletin contains information about 2 vulnerabilities.
Updated: 25.02.2021
Updated description for vulnerability #1.
1) Cross-site request forgery
EUVDB-ID: #VU50471
Risk: Medium
CVSSv3.1: 5.9 [CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L/E:P/RL:O/RC:C]
CVE-ID: CVE-2021-24085
CWE-ID:
CWE-352 - Cross-Site Request Forgery (CSRF)
Exploit availability: Yes
DescriptionThe vulnerability allows a remote attacker to perform cross-site request forgery attacks.
The vulnerability exists due to insecure generation of CSRF tokens for office-addins installation within the HasValidCanary function inside of the Canary15 class. A remote user can trick the victim to visit a specially crafted web page and escalate privileges on the server.
Install update from vendor's website.
Vulnerable software versionsMicrosoft Exchange Server: 2016 Cumulative Update 1 15.01.0396.030 - 2019 RTM 15.02.0221.012
External linkshttp://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-24085
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.
2) Spoofing attack
EUVDB-ID: #VU50472
Risk: Medium
CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-1730
CWE-ID:
CWE-451 - User Interface (UI) Misrepresentation of Critical Information (Clickjacking, spoofing)
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform spoofing attack.
The vulnerability exists due to incorrect processing of user-supplied data in the Exchange Server Installer. A remote attacker can spoof page content.
MitigationInstall updates from vendor's website.
Vulnerable software versionsMicrosoft Exchange Server: 2016 Cumulative Update 18 15.01.2106.002 - 2019 Cumulative Update 7 15.02.0721.002
External linkshttp://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-1730
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
