CVE-2021-34781
A vulnerability in the processing of SSH connections for multi-instance deployments of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the affected device.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.39%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
A vulnerability in the processing of SSH connections for multi-instance deployments of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the affected device. This vulnerability is due to a lack of proper error handling when an SSH session fails to be established. An attacker could exploit this vulnerability by sending a high rate of crafted SSH connections to the instance. A successful exploit could allow the attacker to cause resource exhaustion, which causes a DoS condition on the affected device. The device must be manually reloaded to recover.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 1.39% probability · 71th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-119, CWE-755
- Affected
- cisco/firepower management center virtual appliance · cisco/secure firewall threat defense · cisco/sourcefire defense center
- Source
- psirt@cisco.com
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.