Vulnerability Details : CVE-2021-31207
Microsoft Exchange Server Security Feature Bypass Vulnerability
Vulnerability category: Directory traversal
At least one public exploit which can be used to exploit this vulnerability exists!
CVE-2021-31207
is in the CISA Known Exploited Vulnerabilities Catalog
CISA vulnerability name:
Microsoft Exchange Server Security Feature Bypass Vulnerability
CISA required action:
Apply updates per vendor instructions.
CISA description:
Microsoft Exchange Server contains an unspecified vulnerability that allows for security feature bypass.
Added on
2021-11-03
Action due date
2021-11-17
Exploit prediction scoring system (EPSS) score for CVE-2021-31207
Probability of exploitation activity in the next 30 days: 95.40%
Percentile, the proportion of vulnerabilities that are scored at or less: ~ 99 % EPSS Score History EPSS FAQ
Metasploit modules for CVE-2021-31207
-
Microsoft Exchange ProxyShell RCE
Disclosure Date : 2021-04-06exploit/windows/http/exchange_proxyshell_rceThis module exploits a vulnerability on Microsoft Exchange Server that allows an attacker to bypass the authentication (CVE-2021-31207), impersonate an arbitrary user (CVE-2021-34523) and write an arbitrary file (CVE-2021-34473) to achieve the RCE (Remote Code Execution). By taking advantage of this vulnerability, you can execute arbitrary commands on the remote Microsoft Exchange Server. This vulnerability affects Exchange 2013 CU23 < 15.0.1497.15, Exchange 2016 CU19 < 15.1.2176.12, Exchange 2016 CU20 < 15.1.2242.5, Exchange 2019 CU8 < 15.2.792.13, Exchange 2019 CU9 < 15.2.858.9. All components are vulnerable by default.
CVSS scores for CVE-2021-31207
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|
|
6.5
|
MEDIUM | AV:N/AC:L/Au:S/C:P/I:P/A:P |
8.0
|
6.4
|
[email protected] |
|
7.2
|
HIGH | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
1.2
|
5.9
|
[email protected] |
|
6.6
|
MEDIUM | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H |
0.7
|
5.9
|
[email protected] |
CWE ids for CVE-2021-31207
-
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.Assigned by: [email protected] (Primary)
References for CVE-2021-31207
-
http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html
Exploit;Third Party Advisory;VDB Entry
-
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31207
Patch;Vendor Advisory
-
https://www.zerodayinitiative.com/advisories/ZDI-21-819/
Third Party Advisory;VDB Entry
Products affected by CVE-2021-31207
- cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_20:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_9:*:*:*:*:*:*