CVE-2017-18549 in Linux
Summary
by MITRE
An issue was discovered in drivers/scsi/aacraid/commctrl.c in the Linux kernel before 4.13. There is potential exposure of kernel stack memory because aac_send_raw_srb does not initialize the reply structure.
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Analysis
by VulDB Data Team • 08/10/2025
The vulnerability identified as CVE-2017-18549 represents a critical information disclosure flaw within the Linux kernel's aacraid storage driver subsystem. This issue affects systems running Linux kernel versions prior to 4.13 and specifically targets the communication control component responsible for managing storage requests. The flaw exists in the drivers/scsi/aacraid/commctrl.c source file where the aac_send_raw_srb function fails to properly initialize the reply structure before processing storage commands. This improper initialization creates a scenario where sensitive kernel stack memory contents may be inadvertently exposed to user-space applications through the storage driver interface.
The technical nature of this vulnerability aligns with CWE-119, which addresses improper access to memory locations, and more specifically relates to CWE-200, which covers exposure of sensitive information. The flaw stems from a classic buffer over-read condition where uninitialized memory regions contain residual data from previous operations. When the aac_send_raw_srb function processes storage requests, it relies on a reply structure that should be properly cleared before use. However, the absence of proper initialization means that portions of the structure may contain leftover data from previous operations, potentially including kernel stack contents, memory addresses, or other sensitive information that could be accessed by malicious processes.
The operational impact of this vulnerability extends beyond simple information disclosure, as it could potentially enable attackers to gather intelligence about the kernel memory layout, system state, or even extract sensitive data from kernel memory spaces. This information exposure could facilitate more sophisticated attacks by providing attackers with insights into kernel memory organization, potentially aiding in exploitation of other vulnerabilities or bypassing security mechanisms. The vulnerability is particularly concerning because it affects storage driver functionality, which is commonly used in enterprise environments where systems may be running older kernel versions that have not yet been updated to include the fix.
Mitigation strategies for CVE-2017-18549 primarily involve updating to Linux kernel version 4.13 or later where the fix has been implemented. The patch addresses the issue by ensuring proper initialization of the reply structure before it is used in the communication control process. Organizations should also consider implementing additional monitoring and logging to detect potential exploitation attempts targeting this vulnerability. System administrators should prioritize patching affected systems, particularly those running enterprise storage solutions that rely on the aacraid driver. The vulnerability demonstrates the importance of proper memory initialization practices in kernel space code and highlights the need for comprehensive security testing of device drivers, which aligns with ATT&CK technique T1068 for privilege escalation through kernel exploits. Additionally, this vulnerability underscores the broader category of information disclosure threats that can arise from improper memory management in kernel modules, making it a critical concern for system security hardening efforts.