CVE-2019-10053 in Suricata
Summary
by MITRE
An issue was discovered in Suricata 4.1.x before 4.1.4. If the input of the function SSHParseBanner is composed only of a \n character, then the program runs into a heap-based buffer over-read. This occurs because the erroneous search for \r results in an integer underflow.
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Analysis
by VulDB Data Team • 09/17/2023
The vulnerability identified as CVE-2019-10053 represents a critical heap-based buffer over-read flaw within the Suricata network intrusion detection system version 4.1.x prior to 4.1.4. This issue specifically manifests within the SSHParseBanner function which processes SSH banner information during network traffic analysis. The vulnerability arises from improper input validation and memory management handling when processing malformed SSH protocol data streams, creating a scenario where attackers can manipulate the parsing logic to trigger memory corruption.
The technical root cause of this vulnerability stems from an integer underflow condition that occurs during the search operation within the SSHParseBanner function. When the input data consists solely of a single character, the function's internal calculations fail to properly handle the boundary conditions, leading to an improper memory access pattern. This integer underflow results in the program attempting to read beyond the allocated heap memory boundaries, causing a buffer over-read condition that can potentially expose sensitive memory contents or lead to application instability. The vulnerability aligns with CWE-121 which describes heap-based buffer overflow conditions, and specifically manifests as a memory safety issue in the context of protocol parsing operations.
The operational impact of this vulnerability extends beyond simple application crashes, as it creates potential attack vectors for remote code execution or information disclosure. An attacker capable of sending specially crafted SSH banner data to a vulnerable Suricata system could trigger the buffer over-read condition, potentially allowing for memory corruption that might be exploited to execute arbitrary code or extract sensitive information from the application's memory space. This represents a significant concern for network security monitoring systems that rely on Suricata for SSH traffic inspection, as the vulnerability could be leveraged to compromise the integrity of security monitoring infrastructure.
Mitigation strategies for CVE-2019-10053 focus primarily on upgrading to Suricata version 4.1.4 or later, which includes proper input validation and memory boundary checks within the SSHParseBanner function. Organizations should also implement network segmentation and monitoring to detect unusual SSH traffic patterns that might indicate exploitation attempts. Additional defensive measures include configuring Suricata to limit the processing of SSH-related traffic or implementing rate limiting controls to prevent abuse of the vulnerable parsing function. From an ATT&CK framework perspective, this vulnerability maps to techniques involving command and control communications and privilege escalation, as the exploitation could potentially allow attackers to gain unauthorized access to network monitoring systems and their associated data.