Vulnerability Details : CVE-2021-34523
Public exploit exists!
Used for ransomware!
Microsoft Exchange Server Elevation of Privilege Vulnerability
Vulnerability category: BypassGain privilege
Products affected by CVE-2021-34523
- 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:*:*:*:*:*:*
CVE-2021-34523 is in the CISA Known Exploited Vulnerabilities Catalog
This issue is known to have been leveraged as part of a ransomware campaign.
CISA vulnerability name:
Microsoft Exchange Server Privilege Escalation Vulnerability
CISA required action:
Apply updates per vendor instructions.
CISA description:
Microsoft Exchange Server contains an unspecified vulnerability that allows for privilege escalation.
Notes:
https://nvd.nist.gov/vuln/detail/CVE-2021-34523
Added on
2021-11-03
Action due date
2021-11-17
Exploit prediction scoring system (EPSS) score for CVE-2021-34523
84.81%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 99 %
Percentile, the proportion of vulnerabilities that are scored at or less
Metasploit modules for CVE-2021-34523
-
Microsoft Exchange ProxyShell RCE
Disclosure Date: 2021-04-06First seen: 2022-12-23exploit/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 Cod
CVSS scores for CVE-2021-34523
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
7.5
|
HIGH | AV:N/AC:L/Au:N/C:P/I:P/A:P |
10.0
|
6.4
|
NIST | |
|
9.8
|
CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
3.9
|
5.9
|
NIST | |
|
9.0
|
CRITICAL | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N |
2.5
|
5.8
|
Microsoft Corporation |
CWE ids for CVE-2021-34523
-
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.Assigned by: nvd@nist.gov (Primary)
References for CVE-2021-34523
-
http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html
Microsoft Exchange ProxyShell Remote Code Execution ≈ Packet StormExploit;Third Party Advisory;VDB Entry
-
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34523
CVE-2021-34523 - Security Update Guide - Microsoft - Microsoft Exchange Server Elevation of Privilege VulnerabilityPatch;Vendor Advisory
-
https://www.zerodayinitiative.com/advisories/ZDI-21-822/
ZDI-21-822 | Zero Day InitiativeThird Party Advisory;VDB Entry
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