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Exploited vulnerability · CISA KEV

Is CVE-2023-41763 exploited? Yes: in CISA KEV since 10 Oct 2023

Gociux · Microsoft Skype for Business · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2023-41763, Microsoft Skype for Business Privilege Escalation Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 10 Oct 2023, the day it was published. It affects Microsoft Skype for Business. If you run it, CISA's required action is: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

exploitedYesCISA KEV · 10 Oct 2023
ransomwareNot knownno confirmed use
EPSStop 1%among the most likely CVEs to be exploited
severity5.3CVSS 3.1 · medium
US federal due31 Oct 2023BOD 22-01 deadline

What it is

Microsoft Skype for Business contains an unspecified vulnerability that allows for privilege escalation.

VendorMicrosoft (391 exploited CVEs in KEV)
ProductSkype for Business
VulnerabilityMicrosoft Skype for Business Privilege Escalation Vulnerability
WeaknessCWE-918
Published10 Oct 2023
Added to KEV10 Oct 2023
Reported by (CNA)microsoft

What to do

  1. Check whether you run it. Look for Skype for Business in your asset inventory, including appliances and cloud images. Stack check lists every exploited Microsoft CVE at once.
  2. Apply the fix. Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
  3. 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 10 Oct 2023.
  4. Get told next time. Email alerts when CISA adds a CVE for Microsoft.

References

Questions

Is CVE-2023-41763 being exploited?

Yes. CISA added CVE-2023-41763 to the Known Exploited Vulnerabilities catalog on 10 Oct 2023, which means there is reliable evidence of exploitation in the wild.

Is CVE-2023-41763 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-2023-41763?

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. Check Microsoft's advisory for the fixed versions, and if you can't patch quickly, restrict access to the affected Skype for Business 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 October 2023 · Microsoft scorecard · act-now radar.

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