A vulnerability in the Deterministic Random Bit Generator (DRBG), also known as Pseudorandom Number Generator (PRNG), used in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a cryptographic collision, enabling the attacker to discover the private key of an affected device. The vulnerability is due to insufficient entropy in the DRBG when generating cryptographic keys. An attacker could exploit this vulnerability by generating a large number of cryptographic keys on an affected device and looking for collisions with target devices. A successful exploit could allow the attacker to impersonate an affected target device or to decrypt traffic secured by an affected key that is sent to or from an affected target device.

A vulnerability in the implementation of Security Assertion Markup Language (SAML) 2.0 Single Sign-On (SSO) for Clientless SSL VPN (WebVPN) and AnyConnect Remote Access VPN in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to successfully establish a VPN session to an affected device. The vulnerability is due to improper credential management when using NT LAN Manager (NTLM) or basic authentication. An attacker could exploit this vulnerability by opening a VPN session to an affected device after another VPN user has successfully authenticated to the affected device via SAML SSO. A successful exploit could allow the attacker to connect to secured networks behind the affected device.

A vulnerability in the CLI of Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, local attacker to perform a command injection attack. The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by injecting commands into arguments for a specific command. A successful exploit could allow the attacker to execute commands with root privileges.

Multiple vulnerabilities in the Server Message Block (SMB) Protocol preprocessor detection engine for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, adjacent or remote attacker to cause a denial of service (DoS) condition. For more information about these vulnerabilities, see the Details section of this advisory.

A vulnerability in the internal packet-processing functionality of Cisco Firepower Threat Defense (FTD) Software for the Cisco Firepower 2100 Series could allow an unauthenticated, remote attacker to cause an affected device to stop processing traffic, resulting in a denial of service (DoS) condition. The vulnerability is due to a logic error, which may prevent ingress buffers from being replenished under specific traffic conditions. An attacker could exploit this vulnerability by sending a series of crafted packets to an affected device. A successful exploit could allow the attacker to consume all input buffers, which are shared between all interfaces, leading to a queue wedge condition in all active interfaces. This situation would cause an affected device to stop processing any incoming traffic and result in a DoS condition until the device is reloaded manually.

Multiple vulnerabilities in the WebVPN service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the WebVPN portal of an affected device. The vulnerabilities exist because the software insufficiently validates user-supplied input on 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 affected interface or access sensitive browser-based information. An attacker would need administrator privileges on the device to exploit these vulnerabilities.

A vulnerability in the implementation of the Lightweight Directory Access Protocol (LDAP) feature 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 vulnerabilities are due to the improper parsing of LDAP packets sent to an affected device. An attacker could exploit these vulnerabilities by sending a crafted LDAP packet, using Basic Encoding Rules (BER), to be processed by an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

Multiple vulnerabilities in the Server Message Block (SMB) Protocol preprocessor detection engine for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, adjacent or remote attacker to cause a denial of service (DoS) condition. For more information about these vulnerabilities, see the Details section of this advisory.

A vulnerability in the detection engine of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, adjacent attacker to send data directly to the kernel of an affected device. The vulnerability exists because the software improperly filters Ethernet frames sent to an affected device. An attacker could exploit this vulnerability by sending crafted packets to the management interface of an affected device. A successful exploit could allow the attacker to bypass the Layer 2 (L2) filters and send data directly to the kernel of the affected device. A malicious frame successfully delivered would make the target device generate a specific syslog entry.

A vulnerability in the TCP processing engine of Cisco Adaptive Security Appliance (ASA) Software and Cisco 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 vulnerability is due to the improper handling of TCP traffic. An attacker could exploit this vulnerability by sending a specific sequence of packets at a high rate through an affected device. A successful exploit could allow the attacker to temporarily disrupt traffic through the device while it reboots.

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

A vulnerability in the TCP proxy functionality for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to restart unexpectedly, resulting in a denial of service (DoS) condition. The vulnerability is due to an error in TCP-based packet inspection, which could cause the TCP packet to have an invalid Layer 2 (L2)-formatted header. An attacker could exploit this vulnerability by sending a crafted TCP packet sequence to the targeted device. A successful exploit could allow the attacker to cause a DoS condition.

A vulnerability in the TCP ingress handler for the data interfaces that are configured with management access to Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an increase in CPU and memory usage, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient ingress TCP rate limiting for TCP ports 22 (SSH) and 443 (HTTPS). An attacker could exploit this vulnerability by sending a crafted, steady stream of TCP traffic to port 22 or 443 on the data interfaces that are configured with management access to the affected device.

A vulnerability in the WebVPN login process of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause increased CPU utilization on an affected device. The vulnerability is due to excessive processing load for existing WebVPN login operations. An attacker could exploit this vulnerability by sending multiple WebVPN login requests to the device. A successful exploit could allow the attacker to increase CPU load on the device, resulting in a denial of service (DoS) condition.

A vulnerability in the detection engine of Cisco Firepower Threat Defense Software could allow an unauthenticated, remote attacker to cause the unexpected restart of the SNORT detection engine, resulting in a denial of service (DoS) condition. The vulnerability is due to the incomplete error handling of the SSL or TLS packet header during the connection establishment. An attacker could exploit this vulnerability by sending a crafted SSL or TLS packet during the connection handshake. An exploit could allow the attacker to cause the SNORT detection engine to unexpectedly restart, resulting in a partial DoS condition while the detection engine restarts. Versions prior to 6.2.3.4 are affected.

A vulnerability in the Sourcefire tunnel control channel protocol in Cisco Firepower System Software running on Cisco Firepower Threat Defense (FTD) sensors could allow an authenticated, local attacker to execute specific CLI commands with root privileges on the Cisco Firepower Management Center (FMC), or through Cisco FMC on other Firepower sensors and devices that are controlled by the same Cisco FMC. To send the commands, the attacker must have root privileges for at least one affected sensor or the Cisco FMC. The vulnerability exists because the affected software performs insufficient checks for certain CLI commands, if the commands are executed via a Sourcefire tunnel connection. An attacker could exploit this vulnerability by authenticating with root privileges to a Firepower sensor or Cisco FMC, and then sending specific CLI commands to the Cisco FMC or through the Cisco FMC to another Firepower sensor via the Sourcefire tunnel connection. A successful exploit could allow the attacker to modify device configurations or delete files on the device that is running Cisco FMC Software or on any Firepower device that is managed by Cisco FMC.

A vulnerability in the web interface of the Cisco Adaptive Security Appliance (ASA) could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. It is also possible on certain software releases that the ASA will not reload, but an attacker could view sensitive system information without authentication by using directory traversal techniques. The vulnerability is due to lack of proper input validation of the HTTP URL. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected device. An exploit could allow the attacker to cause a DoS condition or unauthenticated disclosure of information. This vulnerability applies to IPv4 and IPv6 HTTP traffic. This vulnerability affects Cisco ASA Software and Cisco Firepower Threat Defense (FTD) Software that is running on the following Cisco products: 3000 Series Industrial Security Appliance (ISA), ASA 1000V Cloud Firewall, ASA 5500 Series Adaptive Security Appliances, ASA 5500-X Series Next-Generation Firewalls, ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, Adaptive Security Virtual Appliance (ASAv), Firepower 2100 Series Security Appliance, Firepower 4100 Series Security Appliance, Firepower 9300 ASA Security Module, FTD Virtual (FTDv). Cisco Bug IDs: CSCvi16029.

A vulnerability in the detection engine of Cisco Firepower System Software could allow an unauthenticated, remote attacker to bypass configured file action policies if an Intelligent Application Bypass (IAB) with a drop percentage threshold is also configured. The vulnerability is due to incorrect counting of the percentage of dropped traffic. An attacker could exploit this vulnerability by sending network traffic to a targeted device. An exploit could allow the attacker to bypass configured file action policies, and traffic that should be dropped could be allowed into the network. Cisco Bug IDs: CSCvf86435.

A vulnerability in the detection engine of Cisco Firepower System Software could allow an unauthenticated, remote attacker to bypass a configured file action policy to drop the Server Message Block (SMB) protocol if a malware file is detected. The vulnerability is due to how the SMB protocol handles a case in which a large file transfer fails. This case occurs when some pieces of the file are successfully transferred to the remote endpoint, but ultimately the file transfer fails and is reset. An attacker could exploit this vulnerability by sending a crafted SMB file transfer request through the targeted device. An exploit could allow the attacker to pass an SMB file that contains malware, which the device is configured to block. This vulnerability affects Cisco Firepower System Software when one or more file action policies are configured, on software releases prior to 6.2.3. Cisco Bug IDs: CSCvc20141.

A vulnerability in the detection engine of Cisco Firepower System Software could allow an unauthenticated, remote attacker to bypass a configured file action policy that is intended to drop the Server Message Block Version 2 (SMB2) and SMB Version 3 (SMB3) protocols if malware is detected. The vulnerability is due to incorrect detection of an SMB2 or SMB3 file based on the total file length. An attacker could exploit this vulnerability by sending a crafted SMB2 or SMB3 transfer request through the targeted device. An exploit could allow the attacker to pass SMB2 or SMB3 files that could be malware even though the device is configured to block them. This vulnerability does not exist for SMB Version 1 (SMB1) files. This vulnerability affects Cisco Firepower System Software when one or more file action policies are configured, on software releases prior to 6.2.3. Cisco Bug IDs: CSCvg68807.