CVE-2021-34741: Cisco Email Security Appliance Denial of Service Vulnerability

A vulnerability in the identity-based firewall (IDFW) rule processing feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass security protections. This vulnerability is due to improper handling of network requests by affected devices configured to use object group search. An attacker could exploit this vulnerability by sending a specially crafted network request to an affected device. A successful exploit could allow the attacker to bypass access control list (ACL) rules on the device, bypass security protections, and send network traffic to unauthorized hosts.

A vulnerability in the software-based SSL/TLS message handler of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL/TLS decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: Datagram TLS (DTLS) messages cannot be used to exploit this vulnerability.

Multiple vulnerabilities in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. These vulnerabilities are due to improper input validation when parsing HTTPS requests. An attacker could exploit these vulnerabilities by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

A vulnerability in the memory management of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper resource management when connection rates are high. An attacker could exploit this vulnerability by opening a significant number of connections on an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) implementation of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker to trigger a denial of service (DoS) condition on an affected device. This vulnerability is due to improper control of a resource. An attacker with the ability to spoof a trusted IKEv2 site-to-site VPN peer and in possession of valid IKEv2 credentials for that peer could exploit this vulnerability by sending malformed, authenticated IKEv2 messages to an affected device. A successful exploit could allow the attacker to trigger a reload of the device.

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.

A vulnerability in SSL/TLS message handler for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability exists because incoming SSL/TLS packets are not properly processed. An attacker could exploit this vulnerability by sending a crafted SSL/TLS packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

A vulnerability in the web-based management interface of Cisco Identity Services Engine (ISE) could allow an authenticated, remote attacker to obtain sensitive information. This vulnerability is due to improper enforcement of administrator privilege levels for low-value sensitive data. An attacker with read-only administrator access to the web-based management interface could exploit this vulnerability by browsing to the page that contains the sensitive data. A successful exploit could allow the attacker to collect sensitive information regarding the configuration of the system.

A vulnerability in the SSH management feature of multiple Cisco Access Points (APs) platforms could allow a local, authenticated user to modify files on the affected device and possibly gain escalated privileges. The vulnerability is due to improper checking on file operations within the SSH management interface. A network administrator user could exploit this vulnerability by accessing an affected device through SSH management to make a configuration change. A successful exploit could allow the attacker to gain privileges equivalent to the root user.

A vulnerability in the disaster recovery feature of Cisco SD-WAN vManage Software could allow an authenticated, remote attacker to gain unauthorized access to user credentials. This vulnerability exists because access to API endpoints is not properly restricted. An attacker could exploit this vulnerability by sending a request to an API endpoint. A successful exploit could allow the attacker to gain unauthorized access to administrative credentials that could be used in further attacks.

A vulnerability in the FTP inspection engine of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass FTP inspection. The vulnerability is due to ineffective flow tracking of FTP traffic. An attacker could exploit this vulnerability by sending crafted FTP traffic through an affected device. A successful exploit could allow the attacker to bypass FTP inspection and successfully complete FTP connections.

Multiple vulnerabilities in the web management framework of Cisco IOS XE Software could allow an authenticated, remote attacker with read-only privileges to gain unauthorized read access to sensitive data or cause the web management software to hang or crash, resulting in a denial of service (DoS) condition. For more information about these vulnerabilities, see the Details section of this advisory.

Multiple vulnerabilities in the web management framework of Cisco IOS XE Software could allow an authenticated, remote attacker with read-only privileges to gain unauthorized read access to sensitive data or cause the web management software to hang or crash, resulting in a denial of service (DoS) condition. For more information about these vulnerabilities, see the Details section of this advisory.

A vulnerability in the web-based management interface of Cisco Unified Communications Manager could allow an authenticated, remote attacker to view sensitive information in the web-based management interface of the affected software. The vulnerability is due to insufficient protection of user-supplied input by the web-based management interface of the affected service. An attacker could exploit this vulnerability by accessing the interface and viewing restricted portions of the software configuration. A successful exploit could allow the attacker to gain access to sensitive information or conduct further attacks.

A vulnerability in the web-based management interface of Cisco AsyncOS software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to access sensitive information on an affected device. The vulnerability is due to insufficient validation of requests that are sent to the web-based management interface. An attacker could exploit this vulnerability by sending a crafted request to the interface of an affected device. A successful exploit could allow the attacker to obtain the IP addresses that are configured on the internal interfaces of the affected device. There is a workaround that addresses this vulnerability.

A vulnerability in Unified Threat Defense (UTD) in Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to improper validation of IPv6 packets through the UTD feature. An attacker could exploit this vulnerability by sending IPv6 traffic through an affected device that is configured with UTD. A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition.