A vulnerability in the remote access VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct a brute force attack in an attempt to identify valid username and password combinations or an authenticated, remote attacker to establish a clientless SSL VPN session with an unauthorized user. This vulnerability is due to improper separation of authentication, authorization, and accounting (AAA) between the remote access VPN feature and the HTTPS management and site-to-site VPN features. An attacker could exploit this vulnerability by specifying a default connection profile/tunnel group while conducting a brute force attack or while establishing a clientless SSL VPN session using valid credentials. A successful exploit could allow the attacker to achieve one or both of the following: Identify valid credentials that could then be used to establish an unauthorized remote access VPN session. Establish a clientless SSL VPN session (only when running Cisco ASA Software Release 9.16 or earlier). Notes: Establishing a client-based remote access VPN tunnel is not possible as these default connection profiles/tunnel groups do not and cannot have an IP address pool configured. This vulnerability does not allow an attacker to bypass authentication. To successfully establish a remote access VPN session, valid credentials are required, including a valid second factor if multi-factor authentication (MFA) is configured. Cisco will release software updates that address this vulnerability. There are workarounds that address this vulnerability.

A vulnerability in the DNS inspection handler 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 condition (DoS) on an affected device. This vulnerability is due to a lack of proper processing of incoming requests. An attacker could exploit this vulnerability by sending crafted DNS requests at a high rate to an affected device. A successful exploit could allow the attacker to cause the device to stop responding, resulting in a DoS condition.

A vulnerability in the web services interface for remote access VPN features of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, but unprivileged, remote attacker to elevate privileges to level 15. This vulnerability is due to improper separation of authentication and authorization scopes. An attacker could exploit this vulnerability by sending crafted HTTPS messages to the web services interface of an affected device. A successful exploit could allow the attacker to gain privilege level 15 access to the web management interface of the device. This includes privilege level 15 access to the device using management tools like the Cisco Adaptive Security Device Manager (ASDM) or the Cisco Security Manager (CSM). Note: With Cisco FTD Software, the impact is lower than the CVSS score suggests because the affected web management interface allows for read access only.

A vulnerability in the web services interface for remote access VPN features of 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. This vulnerability is due to improper input validation when parsing HTTPS requests. An attacker could exploit this vulnerability by sending a crafted 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 an IPsec VPN library of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to read or modify data within an IPsec IKEv2 VPN tunnel. This vulnerability is due to an improper implementation of Galois/Counter Mode (GCM) ciphers. An attacker in a man-in-the-middle position could exploit this vulnerability by intercepting a sufficient number of encrypted messages across an affected IPsec IKEv2 VPN tunnel and then using cryptanalytic techniques to break the encryption. A successful exploit could allow the attacker to decrypt, read, modify, and re-encrypt data that is transmitted across an affected IPsec IKEv2 VPN tunnel.

A vulnerability in the handler for HTTP authentication for resources accessed through the Clientless SSL VPN portal of Cisco Adaptive Security Appliance (ASA) Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device or to obtain portions of process memory from an affected device. This vulnerability is due to insufficient bounds checking when parsing specific HTTP authentication messages. An attacker could exploit this vulnerability by sending malicious traffic to an affected device acting as a VPN Gateway. To send this malicious traffic, an attacker would need to control a web server that can be accessed through the Clientless SSL VPN portal. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition, or to retrieve bytes from the device process memory that may contain sensitive information.

A vulnerability in the remote access SSL VPN features of 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 is due to improper validation of errors that are logged as a result of client connections that are made using remote access VPN. An attacker could exploit this vulnerability by sending crafted requests to an affected system. A successful exploit could allow the attacker to cause the affected device to restart, resulting in a DoS condition.

A vulnerability in the TLS handler of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 1000 Series firewalls could allow an unauthenticated, remote attacker to gain access to sensitive information. The vulnerability is due to improper implementation of countermeasures against the Bleichenbacher attack for cipher suites that rely on RSA for key exchange. An attacker could exploit this vulnerability by sending crafted TLS messages to the device, which would act as an oracle and allow the attacker to carry out a chosen-ciphertext attack. A successful exploit could allow the attacker to perform cryptanalytic operations that may allow decryption of previously captured TLS sessions to the affected device. To exploit this vulnerability, an attacker must be able to perform both of the following actions: Capture TLS traffic that is in transit between clients and the affected device Actively establish a considerable number of TLS connections to the affected device

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 conduct cross-site scripting (XSS) attacks against a user of the web services interface of an affected device. The vulnerabilities are due to insufficient validation of user-supplied input by the web services interface of an affected device. An attacker could exploit these vulnerabilities by persuading a user of the interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the interface or allow the attacker to access sensitive, browser-based information. Note: These vulnerabilities affect only specific AnyConnect and WebVPN configurations. For more information, see the Vulnerable Products section.

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 conduct cross-site scripting (XSS) attacks against a user of the web services interface of an affected device. The vulnerabilities are due to insufficient validation of user-supplied input by the web services interface of an affected device. An attacker could exploit these vulnerabilities by persuading a user of the interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the interface or allow the attacker to access sensitive, browser-based information. Note: These vulnerabilities affect only specific AnyConnect and WebVPN configurations. For more information, see the Vulnerable Products section.

A vulnerability 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 bypass a configured access rule and access parts of the WebVPN portal that are supposed to be blocked. The vulnerability is due to insufficient validation of URLs when portal access rules are configured. An attacker could exploit this vulnerability by accessing certain URLs on the affected device.

A vulnerability in the Secure Sockets Layer (SSL) VPN feature of Cisco Adaptive Security Appliance (ASA) Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition that prevents the creation of new SSL/Transport Layer Security (TLS) connections to an affected device. The vulnerability is due to incorrect handling of Base64-encoded strings. An attacker could exploit this vulnerability by opening many SSL VPN sessions to an affected device. The attacker would need to have valid user credentials on the affected device to exploit this vulnerability. A successful exploit could allow the attacker to overwrite a special system memory location, which will eventually result in memory allocation errors for new SSL/TLS sessions to the device, preventing successful establishment of these sessions. A reload of the device is required to recover from this condition. Established SSL/TLS connections to the device and SSL/TLS connections through the device are not affected. Note: Although this vulnerability is in the SSL VPN feature, successful exploitation of this vulnerability would affect all new SSL/TLS sessions to the device, including management sessions.

A vulnerability in the web-based management interface of Cisco Adaptive Security Appliance (ASA) Software could allow an authenticated, remote attacker to elevate privileges and execute administrative functions on an affected device. The vulnerability is due to insufficient authorization validation. An attacker could exploit this vulnerability by logging in to an affected device as a low-privileged user and then sending specific HTTPS requests to execute administrative functions using the information retrieved during initial login.

ASA 5515-X Adaptive Security Appliance Adaptive Security Appliance (ASA) Software 9.4.x before 9.4.1 Interim, 9.2.x before 9.2.4 Interim, ASA 5510 Adaptive Security Appliance Adaptive Security Appliance (ASA) Software 8.4.x before 8.4.7 Interim, 8.2.x before 8.2.5 Interim, 9.1.x before 9.1.6 Interim, ASA 5555-X Adaptive Security Appliance ASA for Application Centric Infrastructure (ACI) Device Package 1.2.4.x before 1.2.4.8, ASA 5512-X Adaptive Security Appliance ASA for Application Centric Infrastructure (ACI) Device Package 1.2.4.x before 1.2.4.8, ASA 5520 Adaptive Security Appliance Adaptive Security Appliance (ASA) Software 8.2.x before 8.2.5 Interim, 8.4.x before 8.4.7 Interim, 9.1.x before 9.1.6 Interim, ASA 5505 Adaptive Security Appliance Adaptive Security Appliance (ASA) Software 9.2.x before 9.2.4 Interim, 8.4.x before 8.4.7 Interim, 9.1.x before 9.1.6 Interim, ASA 5525-X Adaptive Security Appliance ASA for Application Centric Infrastructure (ACI) Device Package 1.2.4.x before 1.2.4.8, ASA 5512-X Adaptive Security Appliance Adaptive Security Appliance (ASA) Software 9.4.x before 9.4.1 Interim, 9.2.x before 9.2.4 Interim or 9.2.4.SMP, 9.1.x before 9.1.6 Interim, ASA 5545-X Adaptive Security Appliance ASA for Application Centric Infrastructure (ACI) Device Package 1.2.4.x before 1.2.4.8, ASA 5585-X Adaptive Security Appliance ASA for Application Centric Infrastructure (ACI) Device Package 1.2.4.x before 1.2.4.8, ASA 5540 Adaptive Security Appliance Adaptive Security Appliance (ASA) Software 8.2.x before 8.2.5 Interim, 8.4.x before 8.4.7 Interim, 9.1.x before 9.1.6 Interim, ASA 5515-X Adaptive Security Appliance ASA for Application Centric Infrastructure (ACI) Device Package 1.2.4.x before 1.2.4.8, ASA 5555-X Adaptive Security Appliance Adaptive Security Appliance (ASA) Software 9.2.x before 9.2.4 Interim or 9.2.4.SMP, 9.4.x before 9.4.1 Interim, 9.1.x before 9.1.6 Interim, ASA 5580 Adaptive Security Appliance Adaptive Security Appliance (ASA) Software 9.1.x before 9.1.6 Interim, ASA 5585-X Adaptive Security Appliance Adaptive Security Appliance (ASA) Software 9.2.x before 9.2.4 Interim, 9.4.x before 9.4.1 Interim, ASA 5525-X Adaptive Security Appliance Adaptive Security Appliance (ASA) Software 9.4.x before 9.4.1 Interim, 9.2.x before 9.2.4 Interim or 9.2.4.SMP, 9.1.x before 9.1.6 Interim, ASA 5545-X Adaptive Security Appliance Adaptive Security Appliance (ASA) Software 9.4.x before 9.4.1 Interim, 9.2.x before 9.2.4 Interim or 9.2.4.SMP. 9.1.x before 9.1.6 ASA does not check the source of the ARP request or GARP packets for addresses it performs NAT translation for under unspecified conditions.

Cisco Adaptive Security Appliances (ASA) 5500 series devices with software 7.0 before 7.0(8.11), 7.1 and 7.2 before 7.2(5.1), 8.0 before 8.0(5.19), 8.1 before 8.1(2.47), 8.2 before 8.2(2.19), and 8.3 before 8.3(1.8); Cisco PIX Security Appliances 500 series devices; and Cisco Firewall Services Module (aka FWSM) 3.1 before 3.1(20), 3.2 before 3.2(20), 4.0 before 4.0(15), and 4.1 before 4.1(5) allow remote attackers to cause a denial of service (device reload) via a malformed Skinny Client Control Protocol (SCCP) message, aka Bug IDs CSCtg69457 and CSCtl84952.

Cisco Adaptive Security Appliances (ASA) 5500 series devices with software 7.0 before 7.0(8.12), 7.1 and 7.2 before 7.2(5.2), 8.0 before 8.0(5.21), 8.1 before 8.1(2.49), 8.2 before 8.2(3.6), and 8.3 before 8.3(2.7) and Cisco PIX Security Appliances 500 series devices, when transparent firewall mode is configured but IPv6 is not configured, allow remote attackers to cause a denial of service (packet buffer exhaustion and device outage) via IPv6 traffic, aka Bug ID CSCtj04707.

Unspecified vulnerability on Cisco Adaptive Security Appliances (ASA) 5500 series devices with software before 8.3(2) allows remote attackers to cause a denial of service (device crash) via a large number of LAN-to-LAN (aka L2L) IPsec sessions, aka Bug ID CSCth36592.

Unspecified vulnerability on Cisco Adaptive Security Appliances (ASA) 5500 series devices with software before 8.3(2) allows remote attackers to cause a denial of service (device crash) via multicast traffic, aka Bug IDs CSCtg61810 and CSCtg69742.

The Mobile User Security (MUS) service on Cisco Adaptive Security Appliances (ASA) 5500 series devices with software before 8.3(2) does not properly authenticate HTTP requests from a Web Security appliance (WSA), which might allow remote attackers to obtain sensitive information via a HEAD request, aka Bug ID CSCte53635.

Cisco Adaptive Security Appliances (ASA) 5500 series devices with software before 8.3(2) do not properly preserve ACL behavior after a migration, which allows remote attackers to bypass intended access restrictions via an unspecified type of network traffic that had previously been denied, aka Bug ID CSCte46460.