CVE-2022-33259 in 9205 LTE Modem
Summary
by MITRE • 04/13/2023
Memory corruption due to buffer copy without checking the size of input in modem while decoding raw SMS received.
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Analysis
by VulDB Data Team • 04/13/2023
This vulnerability resides in the modem firmware component responsible for processing raw sms messages, representing a classic buffer overflow condition that can lead to memory corruption and potential system compromise. The flaw occurs when the modem receives an sms message containing raw data that exceeds the allocated buffer space during the decoding process, without proper input validation or size checking mechanisms. The vulnerability manifests when the system attempts to copy incoming sms data into a fixed-size buffer without verifying whether the incoming data exceeds the buffer boundaries, creating conditions where adjacent memory locations can be overwritten. This type of vulnerability falls under the common weakness enumeration category CWE-121, which specifically addresses stack-based buffer overflow conditions, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter execution through buffer overflow exploitation.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can potentially allow attackers to execute arbitrary code within the modem's execution environment or cause system instability through denial of service conditions. When an attacker crafts a malicious sms message with oversized data payloads, they can manipulate the modem's memory layout to overwrite critical control structures, function pointers, or return addresses, potentially enabling privilege escalation or complete system compromise. The vulnerability is particularly concerning in mobile network infrastructure where modems handle thousands of sms messages per second, as the attack surface expands significantly with high-volume message processing. The memory corruption can manifest as system crashes, unexpected reboots, or more insidiously, silent data corruption that may go undetected for extended periods.
Mitigation strategies for this vulnerability should focus on implementing robust input validation mechanisms within the modem firmware, including dynamic buffer size checking, proper bounds verification, and defensive programming practices. The recommended approach involves incorporating size validation checks before any buffer copy operations, utilizing safe string handling functions, and implementing memory protection mechanisms such as stack canaries or address space layout randomization. Additionally, network administrators should consider implementing sms message filtering and rate limiting mechanisms at network boundaries to prevent exploitation attempts. The vulnerability demonstrates the critical importance of input validation in embedded systems and mobile communication infrastructure, where firmware-level protections are essential given the limited ability to patch hardware components after deployment. Organizations should also implement comprehensive monitoring solutions to detect anomalous sms message patterns that might indicate exploitation attempts, while maintaining regular firmware update schedules to address known vulnerabilities in modem components.