CVE-2022-33291 in 9205 LTE Modem
Summary
by MITRE • 04/13/2023
Information disclosure in Modem due to buffer over-read while receiving a IP header with malformed length.
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Analysis
by VulDB Data Team • 04/13/2023
This vulnerability exists within modem firmware systems where improper validation of IP header lengths leads to a buffer over-read condition during packet processing. The flaw occurs when the modem receives network packets containing malformed IP header length fields that exceed the allocated buffer boundaries. This type of vulnerability falls under the CWE-121 category of buffer overflow conditions where data is read beyond the allocated memory limits. The root cause stems from inadequate input validation mechanisms within the network protocol stack implementation, specifically in how the modem handles received IP packets with corrupted or maliciously crafted header information. Attackers can exploit this weakness by sending specially crafted network packets with invalid IP header length values that cause the modem to read beyond the intended buffer boundaries, potentially exposing sensitive memory contents including authentication credentials, cryptographic keys, or system configuration data. The vulnerability represents a critical security risk as it can lead to information disclosure without requiring authentication or privileged access to the affected system. This type of information disclosure vulnerability aligns with ATT&CK technique T1005 which focuses on data from local system repositories and T1041 which covers data compression and encryption. The operational impact of this vulnerability extends beyond simple information leakage, as it can provide attackers with sufficient information to conduct more sophisticated attacks such as privilege escalation or further exploitation of the modem's network stack.
The technical implementation flaw manifests when the modem's network processing engine attempts to parse IP headers without proper bounds checking on the header length field. When an attacker crafts a packet with an IP header length that exceeds the actual data available in the packet, the parsing routine reads beyond the allocated buffer space, potentially accessing adjacent memory regions. This over-read condition can occur in various modem implementations including cellular modems, wireless routers, and network gateway devices that process IP traffic. The vulnerability is particularly concerning because it operates at the network protocol level where the modem processes untrusted data from external sources. Memory layout and stack corruption can occur during this over-read scenario, potentially leading to more severe consequences than simple information disclosure. The vulnerability affects systems where the modem firmware lacks proper bounds checking mechanisms in its IP header parsing routines, making it prevalent across various network infrastructure devices that rely on standard IP processing protocols. This flaw demonstrates a fundamental weakness in secure coding practices where input validation is insufficient to handle malformed network traffic.
The security implications of this vulnerability extend significantly beyond the immediate information disclosure threat. An attacker who successfully exploits this vulnerability can potentially extract sensitive information that may include system memory contents, network configuration parameters, or even cryptographic material used for secure communications. The exposure of such information can enable more advanced attacks including man-in-the-middle scenarios, session hijacking, or network reconnaissance activities. The vulnerability can be exploited through remote network access, making it particularly dangerous for devices that are exposed to untrusted network environments such as public Wi-Fi networks or internet-facing network infrastructure. The attack surface includes any network device that processes IP traffic and implements modem functionality, including enterprise routers, home gateways, and industrial network equipment. This vulnerability can be leveraged as a stepping stone for further compromise of the network infrastructure, as the leaked information can provide insights into system configurations and operational parameters that aid in subsequent attack phases. The potential for cascading security issues exists when this vulnerability is combined with other weaknesses in the network stack or system architecture.
Mitigation strategies for this vulnerability should focus on implementing robust input validation mechanisms within the modem firmware's network processing components. The most effective approach involves adding comprehensive bounds checking for IP header length fields before any memory access operations occur during packet parsing. Firmware updates should be prioritized for all affected modem implementations, with particular attention to network infrastructure devices that process untrusted external traffic. Network segmentation and access controls should be implemented to limit exposure of vulnerable systems to untrusted network environments. Additionally, monitoring systems should be deployed to detect anomalous network traffic patterns that may indicate exploitation attempts. The implementation of defensive coding practices including bounds checking, memory safety mechanisms, and secure input validation should be enforced throughout the modem firmware development lifecycle. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in the network stack implementations. Organizations should also consider implementing network intrusion detection systems that can identify and block malformed IP packets that may attempt to exploit this vulnerability. The remediation process requires careful attention to ensure that the bounds checking mechanisms do not introduce performance degradation or compatibility issues with legitimate network traffic processing.