Microsoft Exchange Server Server-Side Request Forgery
CVE-2022-41040 is a high-severity server-side request forgery vulnerability in Microsoft Exchange Server 2013 Cumulative Update 23 from Microsoft, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 15.00.1497.044 as the first without the flaw, so updating Microsoft Exchange Server 2013 Cumulative Update 23 to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on September 30, 2022, which means attacks have been observed in the wild, including in ransomware campaigns.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Microsoft Exchange Server 2013 Cumulative Update 23 to 15.00.1497.044 or a later version.
- Update Microsoft Exchange Server 2016 Cumulative Update 22 to 15.01.2375.037 or a later version.
- Update Microsoft Exchange Server 2019 Cumulative Update 11 to 15.02.0986.036 or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on msrc.microsoft.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Microsoft | Microsoft Exchange Server 2013 Cumulative Update 23 | 15.00.0 up to, but not including, 15.00.1497.044 | 15.00.1497.044 |
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 22 | 15.0.0 up to, but not including, 15.01.2375.037 | 15.01.2375.037 |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 11 | 15.02.0 up to, but not including, 15.02.0986.036 | 15.02.0986.036 |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 12 | 15.02.0 up to, but not including, 15.02.1118.020 | 15.02.1118.020 |
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 23 | 15.01.0 up to, but not including, 15.01.2507.016 | 15.01.2507.016 |
| Microsoft | Exchange Server | 2013; 2016; 2019 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (microsoft.com).
Official description
Microsoft Exchange Server Elevation of Privilege Vulnerability
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Server-Side Request Forgery
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
How developers prevent this class of flaw
- If there is a known list of applications, IP, hostname, and/or domains to which the product is allowed to communicate, then use allowlists to ensure that outgoing requests are restricted to these known entities. The allowlists could be in the application code or possibly enforced by firewalls or network segmentation.
- If the product is expected to be able to connect to arbitrary IP addresses or domains, consider using a denylist that includes private network addresses, internal domain names, etc. The denylist could be in the application code or possibly enforced by firewalls or network segmentation.
Timeline
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- CVE record published.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- kb.cert.org/vuls/id/915563Third Party Advisory, US Government Resource
- secpod.com/blog/microsoft-november-2022-patch-tuesday-patches-65-vulnerabilities-including-6-zero-days/Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2022-41040US Government Resource
Technical write-ups (may include proof of concept)
- packetstormsecurity.com/files/170066/Microsoft-Exchange-ProxyNotShell-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
Other vulnerabilities in Microsoft Exchange Server 2013 Cumulative Update 23
- 8.8 High severity
- 9.8 Critical severity
- 8.0 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.5 High severity
Recent Server-Side Request Forgery vulnerabilities
- 7.2 High severity
- 7.5 High severity
- 7.5 High severity
- 9.8 Critical severity
- 8.8 High severity
- 8.4 High severity
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