CVE-2020-3555

A vulnerability in the VPN web client services component of Cisco ASA and FTD Software could allow an unauthenticated, remote attacker to conduct browser-based attacks against users. The issue is due to improper validation of input passed to the component before being returned to the browser. An attacker could exploit this by persuading a user to visit a website that sends malicious requests to an affected device with VPN web services enabled.

A vulnerability in the DRBG (PRNG) used in Cisco ASA and FTD Software could allow an unauthenticated, remote attacker to cause a cryptographic collision, enabling discovery of the private key of an affected device. The issue is due to insufficient entropy in the DRBG when generating cryptographic keys. An attacker could exploit this by generating many keys and looking for collisions with target devices.

A vulnerability in the Lightweight Directory Access Protocol (LDAP) feature implementation in 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. The issue is due to improper parsing of LDAP packets. An attacker could send a crafted LDAP packet using Basic Encoding Rules (BER), causing the device to reload.

A vulnerability in the WebVPN service of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition. The issue is due to improper management of authenticated sessions in the WebVPN portal. An attacker could authenticate with valid credentials and access a specific URL, causing the device to reload and resulting in temporary DoS.

A vulnerability in the TCP syslog module of Cisco ASA and FTD Software could allow an unauthenticated, remote attacker to exhaust 1550-byte buffers on an affected device, causing a DoS condition. The issue is due to a missing boundary check in an internal function. An attacker could exploit this by performing a man-in-the-middle attack between the device and its TCP syslog server and modifying TCP headers.

A vulnerability in the per-user-override feature of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass an access control list (ACL) configured for an interface. The issue is due to errors that could occur when constructing and applying per-user-override rules. An attacker could connect to a network through an affected device, potentially accessing resources that would typically be protected by the interface ACL.