CVE-2023-22741 in Sofia-SIP
Summary
by MITRE • 01/20/2023
Sofia-SIP is an open-source SIP User-Agent library, compliant with the IETF RFC3261 specification. In affected versions Sofia-SIP **lacks both message length and attributes length checks** when it handles STUN packets, leading to controllable heap-over-flow. For example, in stun_parse_attribute(), after we get the attribute's type and length value, the length will be used directly to copy from the heap, regardless of the message's left size. Since network users control the overflowed length, and the data is written to heap chunks later, attackers may achieve remote code execution by heap grooming or other exploitation methods. The bug was introduced 16 years ago in sofia-sip 1.12.4 (plus some patches through 12/21/2006) to in tree libs with git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@3774 d0543943-73ff-0310-b7d9-9358b9ac24b2. Users are advised to upgrade. There are no known workarounds for this vulnerability.
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Analysis
by VulDB Data Team • 01/20/2023
The vulnerability identified as CVE-2023-22741 affects Sofia-SIP, an open-source Session Initiation Protocol User-Agent library that implements the IETF RFC3261 specification. This library serves as a foundational component for SIP-based communication systems and is widely used in VoIP applications and telephony solutions. The flaw exists in the STUN packet handling mechanism where the software fails to perform adequate validation of message length and attribute length parameters. This absence of proper bounds checking creates a critical heap-based buffer overflow condition that can be exploited remotely. The vulnerability is particularly concerning because it has remained unpatched for over a decade, with the problematic code introduced in version 1.12.4 and subsequently modified through December 21, 2006, according to the git-svn history. The issue specifically manifests in the stun_parse_attribute() function where attribute length values are used directly for memory copying operations without verifying whether the specified length exceeds the available message buffer space.
The technical implementation of this vulnerability stems from the lack of input validation during STUN packet processing. When parsing STUN attributes, the system retrieves the attribute type and length fields from incoming network packets, but immediately uses the length value to perform heap memory operations without first confirming that the specified length is within acceptable bounds relative to the remaining message data. This flaw allows attackers who control network traffic to craft malicious STUN packets with oversized length fields, enabling them to write data beyond the allocated heap buffer boundaries. The heap overflow occurs because the system treats the attacker-controlled length value as a direct specification for memory copy operations, bypassing all safety mechanisms that would normally prevent such overflows. The vulnerability is classified as a classic heap buffer overflow with a potential for remote code execution, making it particularly dangerous in network-facing applications.
The operational impact of CVE-2023-22741 extends beyond simple memory corruption, as it presents a pathway for sophisticated exploitation techniques. Attackers can leverage this vulnerability through heap grooming methods to achieve remote code execution, potentially compromising systems running vulnerable versions of Sofia-SIP. The vulnerability affects any application or service that utilizes Sofia-SIP for handling STUN packets, which includes numerous VoIP implementations, telephony gateways, and unified communications platforms. The long-standing nature of this flaw means that numerous production systems may be exposed without awareness, particularly in environments where legacy software components persist. Given that STUN packets are commonly exchanged in VoIP communications, the attack surface is substantial, potentially allowing adversaries to target not just individual systems but entire communication infrastructures. This vulnerability directly relates to CWE-121, heap-based buffer overflow, and aligns with ATT&CK techniques involving remote code execution through memory corruption vulnerabilities.
Mitigation strategies for CVE-2023-22741 require immediate action from affected organizations, as there are no viable workarounds available for this specific vulnerability. The primary and recommended solution involves upgrading to a patched version of Sofia-SIP that implements proper bounds checking for STUN attribute lengths. Organizations should conduct comprehensive inventory assessments to identify all systems utilizing vulnerable versions of the library, particularly those involved in VoIP communications, SIP-based services, or telephony infrastructure. The vulnerability's exposure window of over 16 years suggests that many systems may be running unpatched versions, requiring careful risk assessment and remediation planning. Security teams should also implement network monitoring to detect suspicious STUN traffic patterns that might indicate exploitation attempts, while simultaneously preparing for potential post-exploitation activities. Given the nature of heap-based vulnerabilities, system administrators should consider implementing additional security measures such as heap protection mechanisms, address space layout randomization, and other exploit mitigations to reduce the likelihood of successful exploitation even if patching is delayed.