CVE-2022-20688 - Cisco ATA 190 Series Analog Telephone Adapter Firmware Vulnerability: Executing Arbitrary Code and Causing Service Restarts

Cisco has recently identified a vulnerability (CVE-2022-20688) in the Cisco Discovery Protocol functionality of the Cisco ATA 190 Series Analog Telephone Adapter firmware. This vulnerability allows an unauthenticated, remote attacker to execute arbitrary code on an affected device and cause Cisco Discovery Protocol service to restart. If exploited successfully, the attacker would be able to execute code on the device and cause the service to restart unexpectedly, resulting in a Denial of Service (DoS) condition.

Code Snippet

The vulnerability is due to missing length validation of certain Cisco Discovery Protocol packet header fields. The following is a sample malicious Cisco Discovery Protocol packet code snippet that an attacker might use to exploit the vulnerability.

// Malicious Cisco Discovery Protocol Packet
C_DP_PACKET = {
  "Version": 2, 
  "Time_To_Live": 180,
  // Malicious Type-Length-Value (TLV) Structure
  "Malicious_TLV": {
    "Type": x0001,  // Malicious TLV Type
    "Length": xFFFF // Missing Length Validation
  },
  "Data": b"\x41" * 4096 // Arbitrary code
}

The attacker would need to send this malicious packet to an affected device in order to exploit the vulnerability.

To exploit this vulnerability, an attacker would need to perform the following steps

1. Craft a malicious Cisco Discovery Protocol packet, as shown in the code snippet, with a missing length validation.

Send the malicious packet to the affected Cisco ATA 190 Series Analog Telephone Adapter device.

A successful exploit would allow the attacker to execute arbitrary code on the affected device and cause the Cisco Discovery Protocol service to restart unexpectedly. This would result in a DoS condition, where the affected device would be unable to process requests and function effectively.

Original References

- Cisco Security Advisory: Cisco ATA 190 Series Analog Telephone Adapter Firmware Cisco Discovery Protocol Remote Code Execution Vulnerability
- National Vulnerability Database (NVD)

Mitigation

Cisco has released a free software update to address this vulnerability, which can be found at the official website. It is important to apply the software updates as soon as possible to protect your devices from potential attacks. Additionally, ensure your network infrastructure is segmented, and allow only authorized devices to participate in the Cisco Discovery Protocol.

In conclusion, staying informed about vulnerabilities like CVE-2022-20688 and applying the necessary patches and updates is crucial for maintaining a secure network environment. Be sure to follow best practices and guidelines to keep your devices and network safe from potential attacks.

Timeline

Published on: 12/12/2022 09:15:00 UTC
Last modified on: 12/14/2022 16:18:00 UTC