CVE-2023-28099 in OpenSIPS
Summary
by MITRE • 03/16/2023
OpenSIPS is a Session Initiation Protocol (SIP) server implementation. Prior to versions 3.1.9 and 3.2.6, if `ds_is_in_list()` is used with an invalid IP address string (`NULL` is illegal input), OpenSIPS will attempt to print a string from a random address (stack garbage), which could lead to a crash. All users of `ds_is_in_list()` without the `$si` variable as 1st parameter could be affected by this vulnerability to a larger, lesser or no extent at all, depending if the data passed to the function is a valid IPv4 or IPv6 address string or not. Fixes will are available starting with the 3.1.9 and 3.2.6 minor releases. There are no known workarounds.
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Analysis
by VulDB Data Team • 04/08/2023
The vulnerability identified as CVE-2023-28099 affects OpenSIPS, a widely deployed Session Initiation Protocol (SIP) server implementation that serves as a critical component in VoIP infrastructure. This flaw resides within the ds_is_in_list() function, which is responsible for validating IP addresses within distributed SIP server lists. The vulnerability represents a classic buffer over-read and improper input validation issue that can lead to system instability and potential denial of service conditions. The flaw specifically manifests when the function processes invalid IP address strings, particularly when NULL values are passed as input parameters, creating a scenario where the application attempts to dereference memory addresses containing stack garbage data.
The technical implementation of this vulnerability stems from inadequate input validation within the ds_is_in_list() function, which fails to properly handle NULL or malformed IP address strings. When such invalid inputs are processed, the function attempts to print string data from random memory addresses, effectively reading stack contents that may contain sensitive information or simply garbage data. This behavior constitutes a memory safety issue that aligns with CWE-125: Out-of-bounds Read and CWE-787: Out-of-bounds Write, as the application operates beyond the boundaries of allocated memory regions. The vulnerability's impact is particularly concerning because it can cause the SIP server to crash or behave unpredictably, potentially disrupting voice communication services that depend on this infrastructure. The issue affects all versions prior to 3.1.9 and 3.2.6, making it a significant concern for organizations maintaining older OpenSIPS installations.
The operational impact of CVE-2023-28099 extends beyond simple service disruption to encompass potential information disclosure risks and service availability concerns within VoIP networks. When the vulnerability is exploited, it can lead to unauthorized system crashes that may be difficult to diagnose and recover from, particularly in mission-critical communication environments where SIP servers are essential for maintaining voice services. The vulnerability's exploitation potential varies based on how the ds_is_in_list() function is invoked within different OpenSIPS configurations, with the severity depending on whether the input data consists of valid IPv4 or IPv6 address strings or malformed inputs. This characteristic makes the vulnerability particularly dangerous in production environments where automated scripts or user inputs might inadvertently trigger the problematic code path. From an attacker perspective, this vulnerability could be leveraged as part of a broader attack chain targeting VoIP infrastructure, potentially leading to persistent service disruption or as an initial foothold for further exploitation attempts.
Organizations utilizing OpenSIPS must prioritize immediate remediation by upgrading to version 3.1.9 or 3.2.6, as no effective workarounds exist for this vulnerability. The fix addresses the core input validation issue by ensuring proper handling of NULL and invalid IP address strings within the ds_is_in_list() function. Security teams should conduct comprehensive assessments of their OpenSIPS deployments to identify all instances where this function might be invoked, particularly in configurations that process external inputs or user-provided IP addresses. The vulnerability's presence in the distributed server list functionality makes it particularly relevant to organizations operating large-scale VoIP infrastructures where SIP server lists are frequently updated or dynamically managed. Implementation of this patch should be prioritized alongside other security updates to maintain the integrity of communication services, as the vulnerability's potential for causing system instability could have cascading effects throughout VoIP networks that depend on OpenSIPS for call routing and session management.