CVE-2022-31003 is a heap-based buffer overflow vulnerability identified in the sofia-sip library, an open-source Session Initiation Protocol (SIP) User-Agent library widely used in VoIP communications, including the FreeSWITCH telephony platform. The vulnerability exists in versions of sofia-sip prior to 1.13.8. Specifically, when parsing each line of an SDP (Session Description Protocol) message, the code sets a pointer 'rest' to 'record + 2' without properly validating the bounds. This leads to an out-of-bounds write beyond the null terminator '\0' in memory. An attacker can exploit this by sending a crafted SDP message containing malicious payloads to a vulnerable FreeSWITCH instance, triggering a heap-based buffer overflow. The consequences of this overflow range from causing a denial-of-service (crash) to potentially enabling remote code execution (RCE), depending on the attacker's ability to control the overwritten memory. The vulnerability is classified under CWE-122 (Heap-based Buffer Overflow) and CWE-787 (Out-of-bounds Write). The issue was patched in sofia-sip version 1.13.8, which properly bounds checks the SDP parsing logic to prevent memory corruption. There are no known exploits in the wild reported to date, but the nature of the vulnerability and its presence in widely deployed telephony infrastructure make it a significant risk if left unpatched. The vulnerability requires an attacker to send specially crafted SIP/SDP messages to the target system, which typically does not require authentication, increasing the attack surface. User interaction is not required beyond the target system processing the malicious SIP message.

For European organizations, particularly those relying on FreeSWITCH or other telephony systems using sofia-sip, this vulnerability poses a risk of service disruption and potential compromise of telephony infrastructure. The ability to cause a crash can lead to denial-of-service conditions, impacting business communications, call centers, and emergency services. More critically, the possibility of remote code execution could allow attackers to gain unauthorized access to internal networks, intercept or manipulate voice communications, or pivot to other systems within the organization. This risk is heightened in sectors with critical communication needs such as finance, healthcare, government, and telecommunications providers. Given the widespread use of VoIP technologies in Europe and the strategic importance of secure communications, exploitation could have operational and reputational consequences. Additionally, the vulnerability could be leveraged in targeted attacks or by cybercriminal groups aiming to disrupt services or conduct espionage. The absence of known exploits does not diminish the potential impact, as the vulnerability is straightforward to trigger with crafted network traffic.

Organizations should immediately verify the version of sofia-sip used in their telephony infrastructure and upgrade to version 1.13.8 or later where the vulnerability is patched. For FreeSWITCH users, ensure that the underlying sofia-sip library is updated accordingly. Network-level mitigations include deploying SIP-aware intrusion detection and prevention systems (IDS/IPS) that can detect and block malformed SDP messages or anomalous SIP traffic patterns. Implement strict access controls and segmentation for VoIP infrastructure to limit exposure to untrusted networks. Employ rate limiting and anomaly detection on SIP traffic to reduce the risk of exploitation attempts. Regularly audit and monitor telephony logs for unusual activity or crashes that could indicate exploitation attempts. Additionally, consider disabling or restricting SIP services on public-facing interfaces if not required, and enforce strong authentication and encryption (e.g., TLS, SRTP) to protect signaling and media streams. Finally, maintain an incident response plan tailored to telephony system compromises to enable rapid containment and recovery.