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Known exploited vulnerability

CVE-2023-20198

criticalCVSS 3.1 10.0In CISA KEVEPSS 100%Published · Cisco

The short answer

CVE-2023-20198 affects Cisco Cisco IOS XE Software and is rated critical (CVSS 10.0). CISA added it to the Known Exploited Vulnerabilities catalog on 2023-10-16: attackers are using it, so patch it first.

What it is

Cisco is providing an update for the ongoing investigation into observed exploitation of the web UI feature in Cisco IOS XE Software. We are updating the list of fixed releases and adding the Software Checker. Our investigation has determined that the actors exploited two previously unknown issues. The attacker first exploited CVE-2023-20198 to gain initial access and issued a privilege 15 command to create a local user and password combination. This allowed the user to log in with normal user access. The attacker then exploited another component of the web UI feature, leveraging the new local user to elevate privilege to root and write the implant to the file system. Cisco has assigned CVE-2023-20273 to this issue. CVE-2023-20198 has been assigned a CVSS Score of 10.0. CVE-2023-20273 has been assigned a CVSS Score of 7.2. Both of these CVEs are being tracked by CSCwh87343.

Weakness: CWE-420.

Severity

10.0 critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Exploited (CISA KEV)

Yes, since Oct 16, 2023

Federal due date Oct 20, 2023

EPSS, next 30 days

100%

Higher than 100% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality impact
High
Integrity impact
High
Availability impact
High

What CISA says to do

Verify that instances of Cisco IOS XE Web UI are in compliance with BOD 23-02 and apply mitigations per vendor instructions. For affected products (Cisco IOS XE Web UI exposed to the internet or to untrusted networks), follow vendor instructions to determine if a system may have been compromised and immediately report positive findings to CISA.

Affected products

Cisco IOS XE Software. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2023-20198 being exploited?

Yes. CISA added CVE-2023-20198 to its Known Exploited Vulnerabilities catalog on 2023-10-16, with a federal remediation due date of 2023-10-20.

How do I fix CVE-2023-20198?

CISA's required action: Verify that instances of Cisco IOS XE Web UI are in compliance with BOD 23-02 and apply mitigations per vendor instructions. For affected products (Cisco IOS XE Web UI exposed to the internet or to untrusted networks), follow vendor instructions to determine if a system may have been compromised and immediately report positive findings to CISA.

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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