Exploited vulnerability · CISA KEV
Is CVE-2020-17144 exploited? Yes: in CISA KEV since 3 Nov 2021
Gociux · Microsoft Exchange Server · data: CISA KEV, CVE record, FIRST EPSS
Yes. CVE-2020-17144, Microsoft Exchange Server Remote Code Execution Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 3 Nov 2021, 329 days after it was published. It affects Microsoft Exchange Server. If you run it, CISA's required action is: Apply updates per vendor instructions.
exploitedYesCISA KEV · 3 Nov 2021
ransomwareNot knownno confirmed use
EPSStop 5%very likely to be exploited
severity8.4CVSS 3.1 · high
US federal due3 May 2022BOD 22-01 deadline
What it is
Microsoft Exchange Server improperly validates cmdlet arguments which allow an attacker to perform remote code execution.
| Vendor | Microsoft (391 exploited CVEs in KEV) |
| Product | Exchange Server |
| Vulnerability | Microsoft Exchange Server Remote Code Execution Vulnerability |
| Weakness | CWE-502 |
| Published | 9 Dec 2020 |
| Added to KEV | 3 Nov 2021 |
| Reported by (CNA) | microsoft |
What to do
- Check whether you run it. Look for Exchange Server in your asset inventory, including appliances and cloud images. Stack check lists every exploited Microsoft CVE at once.
- Apply the fix. Apply updates per vendor instructions.
- If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 9 Dec 2020.
- Get told next time. Email alerts when CISA adds a CVE for Microsoft.
Other exploited CVEs in Exchange Server
- CVE-2023-21529: Microsoft Exchange Server Deserialization of Untrusted Data Vulnerability (13 Apr 2026)
- CVE-2021-31196: Microsoft Exchange Server Information Disclosure Vulnerability (21 Aug 2024)
- CVE-2024-21410: Microsoft Exchange Server Privilege Escalation Vulnerability (15 Feb 2024)
- CVE-2022-41080: Microsoft Exchange Server Privilege Escalation Vulnerability (10 Jan 2023)
- CVE-2022-41082: Microsoft Exchange Server Remote Code Execution Vulnerability (30 Sep 2022)
- CVE-2022-41040: Microsoft Exchange Server Server-Side Request Forgery Vulnerability (30 Sep 2022)
References
Questions
Is CVE-2020-17144 being exploited?
Yes. CISA added CVE-2020-17144 to the Known Exploited Vulnerabilities catalog on 3 Nov 2021, which means there is reliable evidence of exploitation in the wild.
Is CVE-2020-17144 used in ransomware attacks?
CISA does not list known ransomware use for it. That can change, and exploitation alone is reason to fix it first.
How do I fix CVE-2020-17144?
Apply updates per vendor instructions. Check Microsoft's advisory for the fixed versions, and if you can't patch quickly, restrict access to the affected Exchange Server and watch it for signs of compromise.
Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in November 2021 · Microsoft scorecard · act-now radar.
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