CVE-2023-29357 Microsoft SharePoint Server: privilege escalation
In plain words: Something running with limited rights can promote itself to full control. Turns a small foothold (like a malicious app) into administrator or system-level access.
Confirmed exploited by CISA on · US federal patch deadline Jan 31, 2024
What to do
- Install Microsoft's security update for SharePoint Server. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Keep a list of every internet-facing server you run so nothing is forgotten.
- Patch anything in this catalog first, ahead of normal patch cycles.
- Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.
The details
- Official name
- Microsoft SharePoint Server Privilege Escalation Vulnerability
- Product
- Microsoft SharePoint Server
- CISA description
- Microsoft SharePoint Server contains an unspecified vulnerability that allows an unauthenticated attacker, who has gained access to spoofed JWT authentication tokens, to use them for executing a network attack. This attack bypasses authentication, enabling the attacker to gain administrator privileges.
- Type of flaw
- Privilege escalation (CWE-303)
- Confirmed exploited
- Jan 10, 2024 — known to be used in ransomware attacks
- US federal patch deadline
- Jan 31, 2024
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Answering about CVE-2023-29357 ·
Questions about CVE-2023-29357
Is CVE-2023-29357 being exploited?
Yes. CISA added CVE-2023-29357 to its Known Exploited Vulnerabilities catalog on Jan 10, 2024, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2023-29357?
Install Microsoft's security update for SharePoint Server. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.
Am I affected by CVE-2023-29357?
Only if you use Microsoft SharePoint Server. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.