CVE-2017-3881
Cisco IOS and IOS XE Remote Code Execution Vulnerability
Description
CVE-2017-3881 is a critical input validation vulnerability affecting Cisco IOS and IOS XE. A vulnerability in the Cisco Cluster Management Protocol (CMP) processing code in Cisco IOS and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a reload of an affected device or remotely execute code with elevated privileges. An attacker can exploit this flaw without authentication over the network. CISA has added this vulnerability to the Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. The EPSS score of 94.28% (99.9th percentile) indicates a significantly elevated exploitation probability.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| cisco | ios | >= 12.2s, <= 15.1\(3\)svs |
| cisco | ios xe | >= 3.2sg, <= 3.9e |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- http://www.securityfocus.com/bid/96960(Third Party Advisory, VDB Entry)
- http://www.securityfocus.com/bid/97391(Third Party Advisory, VDB Entry)
- http://www.securitytracker.com/id/1038059(Third Party Advisory, VDB Entry)
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170317-cmp(Vendor Advisory)
- https://www.exploit-db.com/exploits/41872/(Exploit, Third Party Advisory, VDB Entry)
- https://www.exploit-db.com/exploits/41874/(Broken Link)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-3881(US Government Resource)
Weakness Type
CWE-20: Improper Input Validation
Improper Input Validation is a software weakness where a product receives input or data but does not validate or incorrectly validates that the input has the properties required to process data safely and correctly. This vulnerability occurs when applications accept user-supplied data without verifying that it conforms to expected formats, lengths, types, or ranges. In the case of CVE-2017-3881, this weakness allows attackers to compromise Cisco IOS and IOS XE systems.
Learn more: CWE-20 — Improper Input Validation
Impact Analysis
CVE-2017-3881 carries a CVSS 3.1 base score of 9.8 (CRITICAL), reflecting the serious risk it poses to affected environments. Successful exploitation can lead to complete compromise of data confidentiality, full system integrity compromise, and complete denial of service. The attack vector is network-based with low complexity, meaning exploitation is straightforward and can be reliably repeated. Organizations running Cisco IOS and IOS XE face tangible risk of unauthorized access, data breaches, and operational disruption if this vulnerability remains unpatched.
Exploit Maturity
CVE-2017-3881 is listed in the CISA Known Exploited Vulnerabilities catalog with a remediation deadline of 2022-04-15, confirming that real-world exploitation has been observed. The EPSS score of 94.28% (99.9th percentile) places this vulnerability among those most likely to be exploited. Public exploit code is available in vulnerability databases, lowering the barrier for attackers and increasing the urgency of remediation.
Remediation
- Apply updates per vendor instructions. This is the CISA-mandated remediation action and should be prioritized immediately.
- If patches cannot be applied immediately, restrict network access to the affected IOS and IOS XE management interfaces to only trusted administrative networks using firewall rules or access control lists.
- Monitor vendor security advisories for additional updates and ensure a patch management process is in place for timely deployment.
- Conduct a thorough review of affected systems for signs of prior compromise, including unexpected user accounts, modified configurations, and unusual network activity.
- Implement defense-in-depth measures including network segmentation, intrusion detection systems, and continuous security monitoring for the affected infrastructure.
Technical Details
CVE-2017-3881 is exploitable remotely over the network without any prior authentication. A vulnerability in the Cisco Cluster Management Protocol (CMP) processing code in Cisco IOS and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a reload of an affected device or remotely execute code with elevated privileges. The attack complexity is rated low, meaning no specialized conditions or preparation are needed beyond network access to the target. The scope is unchanged, meaning the impact is confined to the vulnerable component. The CVSS 3.1 base score of 9.8 reflects the combination of these factors and the potential for significant damage to affected systems.
Frequently Asked Questions
Is CVE-2017-3881 being actively exploited?
Yes. CISA has confirmed active exploitation by adding CVE-2017-3881 to the Known Exploited Vulnerabilities catalog. The EPSS score of 94.28% (99.9th percentile) further indicates high exploitation likelihood.
What products are affected by CVE-2017-3881?
CVE-2017-3881 affects Cisco IOS and IOS XE. Specifically, affected products include cisco ios, cisco ios xe.
How do I fix CVE-2017-3881?
Apply updates per vendor instructions. Ensure your systems are updated to the latest patched version. If immediate patching is not feasible, restrict network access to the affected system's management interfaces.
How severe is CVE-2017-3881?
CVE-2017-3881 has a CVSS 3.1 score of 9.8 (CRITICAL). This is a critical vulnerability that should be remediated with the highest priority. The vulnerability enables unauthenticated remote attackers to potentially compromise affected IOS and IOS XE systems.
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