CVE-2019-1635 : What You Need to Know
Learn about CVE-2019-1635 affecting Cisco IP Phone 7800 and 8800 Series. Find out how an attacker could exploit SIP Software to cause a denial of service condition and steps to mitigate the vulnerability.
A vulnerability in the call-handling functionality of Session Initiation Protocol (SIP) Software for Cisco IP Phone 7800 Series and 8800 Series could allow an unauthenticated, remote attacker to cause an affected phone to reload unexpectedly, resulting in a temporary denial of service (DoS) condition.
Understanding CVE-2019-1635
This CVE involves a flaw in the call-handling feature of the SIP Software used in Cisco IP Phone 7800 Series and 8800 Series, potentially leading to a disruptive denial of service situation.
What is CVE-2019-1635?
The vulnerability arises from inadequate error handling during XML data processing in a SIP packet, allowing an attacker to send a malicious XML payload to trigger an unexpected reload of the affected phone.
The Impact of CVE-2019-1635
The vulnerability could result in a temporary DoS condition by causing the affected phone to reload unexpectedly, affecting availability.
Technical Details of CVE-2019-1635
This section provides more technical insights into the vulnerability.
Vulnerability Description
The flaw in the call-handling feature of SIP Software allows an attacker to exploit inadequate error handling during XML data processing in a SIP packet.
Affected Systems and Versions
- Cisco Wireless IP Phone 8821 and 8821-EX with versions less than 11.0(5)
- Cisco IP Phone 7800 Series and 8800 Series with versions less than 12.5(1)
Exploitation Mechanism
- Attacker sends a SIP packet containing a malicious XML payload to a vulnerable phone
- Successful exploitation triggers an unexpected reload of the affected phone, causing a temporary DoS condition
Mitigation and Prevention
Steps to address and prevent the CVE-2019-1635 vulnerability.
Immediate Steps to Take
- Apply vendor-provided patches or updates promptly
- Implement network segmentation to limit exposure
- Monitor network traffic for suspicious activity
Long-Term Security Practices
- Regularly update and patch all software and firmware
- Conduct security training for employees to recognize and report suspicious activities
Patching and Updates
- Cisco has released patches to address the vulnerability
- Ensure all affected systems are updated with the latest patches