Cisco IOS XR Software Intermediate System–to–Intermediate System Denial of Service Vulnerability

A vulnerability in the implementation of Intermediate System–to–Intermediate System (IS–IS) routing protocol functionality in Cisco IOS XR Software could allow an unauthenticated attacker who is in the same IS-IS area to cause a denial of service (DoS) condition.

The vulnerability is due to incorrect processing of IS–IS link-state protocol data units (PDUs). An attacker could exploit this vulnerability by sending specific link-state PDUs to an affected system to be processed. A successful exploit could allow the attacker to cause incorrect calculations used in the weighted remote shared risk link groups (SRLG) or in the IGP Flexible Algorithm. It could also cause tracebacks to the logs or potentially cause the receiving device to crash the IS–IS process, resulting in a DoS condition.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190807-iosxr-isis-dos-1918

A companion advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190807-iosxr-isis-dos-1910

Security Impact Rating: High

CVE: CVE-2019-1918

Related:

  • No Related Posts

Cisco Nexus 9000 Series ACI Mode Switch Software Link Layer Discovery Protocol Buffer Overflow Vulnerability

A vulnerability in the Link Layer Discovery Protocol (LLDP) subsystem of Cisco Nexus 9000 Series Application Centric Infrastructure (ACI) Mode Switch Software could allow an adjacent, unauthenticated attacker to cause a denial of service (DoS) condition or execute arbitrary code with root privileges.

The vulnerability is due to improper input validation of certain type, length, value (TLV) fields of the LLDP frame header. An attacker could exploit this vulnerability by sending a crafted LLDP packet to the targeted device. A successful exploit may lead to a buffer overflow condition that could either cause a DoS condition or allow the attacker to execute arbitrary code with root privileges.

Note: This vulnerability cannot be exploited by transit traffic through the device; the crafted packet must be targeted to a directly connected interface.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190731-nxos-bo

Security Impact Rating: High

CVE: CVE-2019-1901

Related:

  • No Related Posts

Cisco Unified Communications Manager Session Initiation Protocol Denial of Service Vulnerability

A vulnerability in the Session Initiation Protocol (SIP) protocol implementation of Cisco Unified Communications Manager could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.

The vulnerability is due to insufficient validation of input SIP traffic. An attacker could exploit this vulnerability by sending a malformed SIP packet to an affected Cisco Unified Communications Manager. A successful exploit could allow the attacker to trigger a new registration process on all connected phones, temporarily disrupting service.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190703-cucm-dos

Security Impact Rating: High

CVE: CVE-2019-1887

Related:

  • No Related Posts

Cisco IP Phone 7800 and 8800 Series Session Initiation Protocol Denial of Service Vulnerability

A vulnerability in Cisco SIP IP Phone Software for Cisco IP Phone 7800 Series and 8800 Series could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected phone.

The vulnerability is due to insufficient validation of input Session Initiation Protocol (SIP) packets. An attacker could exploit this vulnerability by altering the SIP replies that are sent to the affected phone during the registration process. A successful exploit could allow the attacker to cause the phone to reboot and not complete the registration process.

There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190703-ip-phone-sip-dos

Security Impact Rating: Medium

CVE: CVE-2019-1922

Related:

  • No Related Posts

Behavior of 'Preferred' Option when two NTP servers are added

The Prefer option is an NTP level setting. Not only the ADC, but all devices conform to the rules in the RFC : http://doc.ntp.org/3-5.93e/prefer.html

Case 1: When 2 NTP servers are added with preferred option as YES set for both servers.

-It uses mitigation rules defined in the RFC. http://doc.ntp.org/3-5.93e/prefer.html (Please refer to the Mitigation Rules section)

Case 2: When 2 NTP servers are added with preferred option as YES set for one server, and NO for the other server

-The appliance synchronizes with that particular server first which has preferred option as YES.

Related:

  • No Related Posts

Cisco StarOS Denial of Service Vulnerability

A vulnerability in the internal packet-processing functionality of the Cisco StarOS operating system running on virtual platforms 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 that may occur 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 prevent the targeted service interface from receiving any traffic, which would lead to a DoS condition on the affected interface.

The device may have to be manually reloaded to recover from exploitation of this vulnerability.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190619-staros-asr-dos

Security Impact Rating: High

CVE: CVE-2019-1869

Related:

  • No Related Posts