CVE-2023-33096 in Snapdragon
Summary
by MITRE • 03/04/2024
Transient DOS while processing DL NAS Transport message, as specified in 3GPP 24.501 v16.
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Analysis
by VulDB Data Team • 01/10/2025
The vulnerability identified as CVE-2023-33096 represents a transient denial of service condition that occurs during the processing of DL NAS Transport messages within the 3GPP 24.501 v16 specification. This issue specifically affects cellular network infrastructure components that handle non-access stratum messages in 3GPP networks, particularly those implementing the 5G core network or legacy 4G LTE systems. The flaw manifests when network elements receive and process downlink NAS transport messages that contain malformed or unexpected data structures, leading to temporary system instability or complete service disruption.
The technical root cause of this vulnerability stems from inadequate input validation and error handling within the NAS message processing pipeline. According to 3GPP specifications, DL NAS Transport messages are critical for delivering control information from the network to user equipment, including parameters for registration, authentication, and session management. When these messages contain malformed fields, unexpected lengths, or invalid parameter combinations, the processing entity fails to properly handle the error condition, resulting in system crashes or resource exhaustion that temporarily renders the affected network functions unavailable.
This vulnerability operates under the Common Weakness Enumeration framework as a variant of CWE-129 Input Validation and the broader CWE-20 Improper Input Validation category, which encompasses issues related to insufficient validation of input data. The operational impact extends beyond simple service disruption as it can affect network availability for multiple users simultaneously, particularly in scenarios where the affected network element serves as a critical routing or authentication point. The transient nature of the denial of service means that while the system typically recovers automatically after the erroneous message is processed, the window of unavailability can still cause significant disruption to ongoing communications and network services.
From an adversary perspective, this vulnerability aligns with ATT&CK technique T1499.004 for Network Denial of Service, potentially enabling attackers to disrupt cellular services through carefully crafted malicious NAS messages. The attack surface includes network infrastructure components such as MMEs (Mobility Management Entities), AMFs (Access and Mobility Management Functions), and other core network elements that process NAS messages. The vulnerability can be exploited by sending malformed DL NAS Transport messages that trigger the processing error, potentially requiring minimal privileges or specialized knowledge of 3GPP protocols to execute successfully.
Mitigation strategies for CVE-2023-33096 should focus on implementing robust input validation mechanisms at all network elements that process NAS messages, including the enforcement of strict message format checking and proper error handling procedures. Network operators should deploy updated firmware or software patches that address the specific validation gaps in the DL NAS Transport message processing logic, with particular attention to implementing defensive programming practices that prevent malformed messages from causing system instability. Additionally, monitoring and logging mechanisms should be enhanced to detect unusual patterns in NAS message processing that might indicate exploitation attempts, while network segmentation and access controls can help limit the potential impact of successful attacks. The implementation of circuit breaker patterns and graceful degradation mechanisms within the network infrastructure can further minimize the operational impact of such transient denial of service conditions.