A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS Software running on certain models of Cisco Catalyst Switches could allow an authenticated, remote attacker to cause a denial of service (DoS) condition, aka a GET MIB Object ID Denial of Service Vulnerability. The vulnerability is due to a condition that could occur when the affected software processes an SNMP read request that contains a request for the ciscoFlashMIB object ID (OID). An attacker could trigger this vulnerability by issuing an SNMP GET request for the ciscoFlashMIB OID on an affected device.
A successful exploit could cause the affected device to restart due to a SYS-3-CPUHOG. This vulnerability affects the following Cisco devices if they are running a vulnerable release of Cisco IOS Software and are configured to use SNMP Version 2 (SNMPv2) or SNMP Version 3 (SNMPv3): Cisco Catalyst 2960-L Series Switches, Cisco Catalyst Digital Building Series Switches 8P, Cisco Catalyst Digital Building Series Switches 8U.
Risk to organizations includes potential service disruptions, which can significantly impact network operations. Given the medium severity of this vulnerability with a CVSS score of 6.3, organizations should prioritize patching immediately.
As of now, there is no public exploit confirmed for this vulnerability, but its inclusion in the Known Exploited Vulnerabilities (KEV) catalog highlights its potential risk.
Vulnerability Details
The CVE-2018-0161 vulnerability is specifically associated with the SNMP subsystem of Cisco IOS Software. It allows a remote attacker to exploit the SNMP read request mechanism, causing a Denial of Service. The official description states that the vulnerability is due to the processing of SNMP read requests for the ciscoFlashMIB OID.
The CVSS score for this vulnerability is 6.3, indicating a medium severity level. The attack vector is network-based, and the attack complexity is rated as high, requiring low privileges and no user interaction.
The affected product is Cisco IOS Software, with specific configurations vulnerable to this issue. The vulnerability was published on March 28, 2018, and is associated with CWE-399.
Technical Analysis
The root cause of the CVE-2018-0161 vulnerability lies in the processing mechanisms of SNMP requests within the Cisco IOS Software. When an attacker sends a crafted SNMP GET request specifically targeting the ciscoFlashMIB OID, the affected device may enter a state that causes it to restart, leading to a denial of service.
The attack vector is network-based, meaning an attacker does not need physical access to the device. The complexity of the attack is rated as high, requiring an authenticated user to execute the exploit. Privileges required are low, as minimal access is needed, and user interaction is not required.
The impact of this vulnerability primarily affects the availability of the device. The confidentiality and integrity impacts are none, but availability impact is rated as high, as the device can become unresponsive or restart unexpectedly.
Risk & Impact Analysis
Organizations that deploy affected Cisco devices face significant risks, including service downtime and operational disruptions. The potential blast radius for this vulnerability can extend across networks utilizing these switches, leading to broader availability issues.
Given the medium severity classification, organizations should address this vulnerability in their priority patch cycle. The known exploitation status indicates that it is included in the KEV catalog, suggesting potential exploitation in the wild. Therefore, organizations should act swiftly to mitigate the risk.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | Yes |
Ransomware Use | No |
Affected Versions
The vulnerability affects Cisco IOS Software versions 15.2(5)e and prior. All versions prior to vendor patch are vulnerable.
Mitigation & Remediation
Organizations should apply updates per vendor instructions to remediate this vulnerability. Patch information can be found in the Cisco advisory linked here: Cisco Security Advisory. In cases where a patch is not yet applied, organizations should consider implementing network segmentation to limit exposure and monitor SNMP traffic for anomalies.
Detection Guidance
To detect potential exploitation attempts, organizations should monitor logs for unusual SNMP traffic patterns and look for repeated SNMP GET requests for the ciscoFlashMIB OID. Additionally, monitoring for device restarts or CPU hog conditions can indicate attempted exploitation.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2018-0161 lies in its representation of vulnerabilities that can lead to significant service disruptions when exploited. Security teams should learn from this incident to strengthen defenses against similar vulnerabilities.
Organizations should consider adopting a proactive approach by regularly testing their systems through penetration testing to identify and address vulnerabilities before they can be exploited.
In conclusion, the CVE-2018-0161 vulnerability underscores the importance of timely patching and proactive security measures. By staying informed and prepared, organizations can mitigate risks associated with this and similar vulnerabilities.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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