CVE-2018-8581
Microsoft Exchange Server Privilege Escalation Vulnerability
Description
CVE-2018-8581 is a high-severity privilege escalation vulnerability affecting Microsoft Exchange Server. A privilege escalation vulnerability exists in Microsoft Exchange Server. An attacker who successfully exploited this vulnerability could attempt to impersonate any other user of the Exchange server. CISA has added this vulnerability to its Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. With an EPSS score of 91.5% (99.7th percentile), this vulnerability has a notable probability of exploitation. This vulnerability is known to be used in ransomware campaigns.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:NOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| microsoft | exchange server | 2010; 2013; 2016; 2019 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
References
- http://www.securityfocus.com/bid/105837(Broken Link, Third Party Advisory, VDB Entry)
- http://www.securitytracker.com/id/1042141(Broken Link, Third Party Advisory, VDB Entry)
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8581(Patch, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8581(US Government Resource)
Weakness Type
Unspecified Weakness
No specific CWE has been assigned to this vulnerability. The underlying weakness type is not publicly categorized, but the vulnerability's impact is well-documented through its inclusion in the CISA KEV catalog.
Impact Analysis
CVE-2018-8581 carries a CVSS 3.1 score of 7.4 (HIGH), indicating a high-severity threat. The vulnerability is exploitable over the network though attack complexity is high and requires no authentication. Successful exploitation can severely compromise data confidentiality, and allow unauthorized modification of data and systems. Organizations running affected Exchange Server deployments face significant operational risk if this vulnerability remains unpatched.
Exploit Maturity
CVE-2018-8581 is confirmed as actively exploited through its listing in the CISA Known Exploited Vulnerabilities catalog. The EPSS score of 91.5% (99.7th percentile) reflects an exceptionally high probability of exploitation. This vulnerability has been associated with ransomware campaigns, underscoring the financial and operational risks of delayed patching.
Remediation
- Apply vendor patches immediately as mandated by CISA KEV: Apply updates per vendor instructions.
- Verify that all instances of affected products (microsoft exchange server 2010; 2013; 2016; 2019) have been updated to patched versions.
- If immediate patching is not possible, restrict network access to affected systems using firewall rules and network segmentation to limit exposure.
- Monitor systems for indicators of compromise, including unusual process activity, unexpected network connections, and unauthorized configuration changes.
- Review security logs and conduct threat hunting to determine if the vulnerability was exploited prior to patching.
Technical Details
CVE-2018-8581 affects Microsoft Exchange Server. A privilege escalation vulnerability exists in Microsoft Exchange Server. An attacker who successfully exploited this vulnerability could attempt to impersonate any other user of the Exchange server. The attack vector is network-based, meaning an attacker can exploit this vulnerability remotely without physical access to the target system. The CVSS score of 7.4 reflects a serious vulnerability that poses meaningful risk to affected environments.
Frequently Asked Questions
Is CVE-2018-8581 being actively exploited?
Yes. CVE-2018-8581 is listed in the CISA Known Exploited Vulnerabilities catalog, confirming active exploitation. The EPSS score of 91.5% (99.7th percentile) further indicates a very high exploitation probability. This vulnerability is also known to be used in ransomware campaigns.
What products are affected by CVE-2018-8581?
CVE-2018-8581 affects Microsoft Exchange Server. Specifically affected products include: microsoft exchange server (2010; 2013; 2016; 2019).
How do I fix CVE-2018-8581?
Apply updates per vendor instructions. Ensure all affected systems are updated to the latest patched versions. If patching is not immediately possible, implement network-level mitigations to limit exposure.
How severe is CVE-2018-8581?
CVE-2018-8581 has a CVSS 3.1 score of 7.4 (HIGH). This is a high-severity vulnerability that should be prioritized for remediation.
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