Known exploited vulnerability
CVE-2017-12240
The short answer
CVE-2017-12240 affects n/a Cisco IOS and IOS XE and is rated critical (CVSS 9.8). CISA added it to the Known Exploited Vulnerabilities catalog on 2022-03-03: attackers are using it, so patch it first.
What it is
The DHCP relay subsystem of Cisco IOS 12.2 through 15.6 and Cisco IOS XE Software contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code and gain full control of an affected system. The attacker could also cause an affected system to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to a buffer overflow condition in the DHCP relay subsystem of the affected software. An attacker could exploit this vulnerability by sending a crafted DHCP Version 4 (DHCPv4) packet to an affected system. A successful exploit could allow the attacker to execute arbitrary code and gain full control of the affected system or cause the affected system to reload, resulting in a DoS condition. Cisco Bug IDs: CSCsm45390, CSCuw77959.
Severity
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploited (CISA KEV)
Yes, since Mar 3, 2022
Federal due date Mar 24, 2022
EPSS, next 30 days
14%
Higher than 97% of scored CVEs
How it can be exploited
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
What CISA says to do
Apply updates per vendor instructions.
Affected products
Cisco IOS and IOS XE. NVD's record lists the exact affected versions.
References
- quickview.cloudapps.cisco.com/quickview/bug/CSCsm45390 Vendor Advisory
- quickview.cloudapps.cisco.com/quickview/bug/CSCuw77959 Vendor Advisory
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-dhcp Vendor Advisory
- quickview.cloudapps.cisco.com/quickview/bug/CSCsm45390 Vendor Advisory
- quickview.cloudapps.cisco.com/quickview/bug/CSCuw77959 Vendor Advisory
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-dhcp Vendor Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-12240 US Government Resource
Questions
Is CVE-2017-12240 being exploited?
Yes. CISA added CVE-2017-12240 to its Known Exploited Vulnerabilities catalog on 2022-03-03, with a federal remediation due date of 2022-03-24.
How do I fix CVE-2017-12240?
CISA's required action: Apply updates per vendor instructions.
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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