CVE-2021-27065
Microsoft Exchange Server: Remote Code Execution
As of , CVE-2021-27065 in Microsoft Exchange Server is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.
- Exploited
- Yes: CISA listed it on 3 November 2021
- US federal deadline
- 3 May 2022181 days after CISA listed it. US federal civilian agencies must fix it by then.
- Used in ransomware campaigns
- Known
- EPSS score
- 0.99Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
- EPSS when listed
- Not availableCISA listed it before 4 February 2022, where the EPSS files we read begin.
- Public exploit
- 1 Metasploit module and 1 Exploit-DB entry
- Fix
- No vendor link in CISA's entry
What CISA says to do
Apply updates per vendor instructions.
CISA's required action
What the flaw is
Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution. This vulnerability is part of the ProxyLogon exploit chain.
CISA's description
Microsoft Exchange Server Remote Code Execution Vulnerability
The CVE record's description, from microsoft
- CVE published
- 2 March 2021
- Assigned by
- microsoft
- CVSS
- 7.8 High (CVSS 3.1, from the CNA)
- CWE-22
- Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
- CWE-39
- Path Traversal: 'C:dirname'
- CISA SSVC, exploitation
- active
- CISA SSVC, automatable
- yes
- CISA SSVC, technical impact
- total
Timeline
- The CVE record was published.
- Exploit-DB published an exploit (EDB-ID 49637).
- CISA added it to its list of exploited vulnerabilities.
- The US federal deadline to fix it.
- CISA changed its entry. Deadline moved from 16 April 2021 to 3 May 2022.
Public exploits
Facts from Metasploit's module list and Exploit-DB's index; we never copy exploit code.
- Metasploit: Microsoft Exchange ProxyLogon RCEexploit module, rank excellent
- Exploit-DB: Microsoft Exchange 2019 - Server-Side Request Forgery (Proxylogon) (PoC)EDB-ID 49637, 11 March 2021
Exchange Server: other exploited entries
| Vulnerability | Product | Our group | Listed | Deadline | EPSS |
|---|---|---|---|---|---|
| CVE-2023-21529Deserialization of Untrusted Data | Microsoft Exchange Server | Patch nowRansomware use, listed within a year | 0.59 | ||
| CVE-2020-0688Validation Key Remote Code Execution | Microsoft Exchange Server | Patch this weekRansomware use; Metasploit module; EPSS 0.99; verified Exploit-DB entry | 0.99 | ||
| CVE-2022-41040Server-Side Request Forgery | Microsoft Exchange Server | Patch this weekRansomware use; Metasploit module; EPSS 0.99 | 0.99 | ||
| CVE-2022-41082Remote Code Execution | Microsoft Exchange Server | Patch this weekRansomware use; Metasploit module; EPSS 0.99 | 0.99 | ||
| CVE-2021-26855Remote Code Execution | Microsoft Exchange Server | Patch this weekRansomware use; Metasploit module; EPSS 0.99 | 0.99 | ||
| CVE-2021-31207Security Feature Bypass | Microsoft Exchange Server | Patch this weekRansomware use; Metasploit module; EPSS 0.99 | 0.99 | ||
| CVE-2021-34473Remote Code Execution | Microsoft Exchange Server | Patch this weekRansomware use; Metasploit module; EPSS 0.99 | 0.99 | ||
| CVE-2021-34523Privilege Escalation | Microsoft Exchange Server | Patch this weekRansomware use; Metasploit module; EPSS 0.99 | 0.99 | ||
| CVE-2022-41080Privilege Escalation | Microsoft Exchange Server | Patch this weekRansomware use; EPSS 0.77 | 0.77 | ||
| CVE-2021-33766Information Disclosure | Microsoft Exchange Server | Patch this weekEPSS 0.98 | 0.98 |
Read further
- CVE recordcve.org
- NVD entrynvd.nist.gov
- CISA's catalogcisa.gov
- EPSS for this CVEapi.first.org