Cisco Web Security Appliance Proxy Service Denial of Service Vulnerability
A vulnerability in the proxy service of Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to exhaust system memory and cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper memory management in the proxy service of an affected device. An attacker could exploit this vulnerability by establishing a large number of HTTPS connections to the affected device. A successful exploit could allow the attacker to cause the system to stop processing new connections, which could result in a DoS condition. Note: Manual intervention may be required to recover from this situation. Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2021-34698US | high7.5 | — | ||
A vulnerability in the proxy service of Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to exhaust system memory and cause a de… | ||||
references
External citations — patches, advisories, analysis.
- Cisco Web Security Appliance Proxy Service Denial of Service Vulnerabilityself
- Cisco Security Vulnerability Policyexternal
- considering software upgradesexternal
- https://www.cisco.com/c/en/us/products/end-user-license-agreement.htmlexternal
- https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.htmlexternal
- Cisco Security Advisories pageexternal
remediations (2)
- FixedCisco Secure Web Appliance
Cisco has released software updates that address this vulnerability.
https://software.cisco.com - WorkaroundCisco Secure Web Appliance
There is a workaround that addresses this vulnerability. Customers can use the hidden diagnostic > PROXY > KICK command to restart the proxy process and reclaim memory. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.
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