#dos

The OPENSSL_LH_flush() function, which empties a hash table, contains a bug that breaks reuse of the memory occuppied by the removed hash table entries. This function is used when decoding certificates or keys. If a long lived process periodically decodes certificates or keys its memory usage will expand without bounds and the process might be terminated by the operating system causing a denial of service. Also traversing the empty hash table entries will take increasingly more time. Typically such long lived processes might be TLS clients or TLS servers configured to accept client certificate authentication. The function was added in the OpenSSL 3.0 version thus older releases are not affected by the issue. Fixed in OpenSSL 3.0.3 (Affected 3.0.0,3.0.1,3.0.2).

The c_rehash script does not properly sanitise shell metacharacters to prevent command injection. This script is distributed by some operating systems in a manner where it is automatically executed. On such operating systems, an attacker could execute arbitrary commands with the privileges of the script. Use of the c_rehash script is considered obsolete and should be replaced by the OpenSSL rehash command line tool. Fixed in OpenSSL 3.0.3 (Affected 3.0.0,3.0.1,3.0.2). Fixed in OpenSSL 1.1.1o (Affected 1.1.1-1.1.1n). Fixed in OpenSSL 1.0.2ze (Affected 1.0.2-1.0.2zd).

Ubuntu Security Notice 5399-1 - It was discovered that libvirt incorrectly handled certain locking operations. A local attacker could possibly use this issue to cause libvirt to stop accepting connections, resulting in a denial of service. This issue only affected Ubuntu 20.04 LTS. It was discovered that libvirt incorrectly handled threads during shutdown. A local attacker could possibly use this issue to cause libvirt to crash, resulting in a denial of service. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS.

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 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 connection handling function in 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 traffic handling when platform limits are reached. An attacker could exploit this vulnerability by sending a high rate of UDP traffic through an affected device. A successful exploit could allow the attacker to cause all new, incoming connections to be dropped, resulting in a DoS condition.

A vulnerability in the Snort detection engine integration for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause unlimited memory consumption, which could lead to a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient memory management for certain Snort events. An attacker could exploit this vulnerability by sending a series of crafted IP packets that would generate specific Snort events on an affected device. A sustained attack could cause an out of memory condition on the affected device. A successful exploit could allow the attacker to interrupt all traffic flowing through the affected device. In some circumstances, the attacker may be able to cause the device to reload, resulting in a DoS condition.

A vulnerability in the Snort rule evaluation function of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper handling of the DNS reputation enforcement rule. An attacker could exploit this vulnerability by sending crafted UDP packets through an affected device to force a buildup of UDP connections. A successful exploit could allow the attacker to cause traffic that is going through the affected device to be dropped, resulting in a DoS condition. Note: This vulnerability only affects Cisco FTD devices that are running Snort 3.

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 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.