CVE-2017-7277 in Linux
Summary
by MITRE
The TCP stack in the Linux kernel through 4.10.6 mishandles the SCM_TIMESTAMPING_OPT_STATS feature, which allows local users to obtain sensitive information from the kernel's internal socket data structures or cause a denial of service (out-of-bounds read) via crafted system calls, related to net/core/skbuff.c and net/socket.c.
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Analysis
by VulDB Data Team • 11/22/2022
The vulnerability identified as CVE-2017-7277 represents a critical flaw in the Linux kernel's TCP stack implementation that affects versions through 4.10.6. This issue stems from improper handling of the SCM_TIMESTAMPING_OPT_STATS feature, which is part of the socket control message infrastructure designed to provide detailed timing information for network packets. The flaw exists within the kernel's networking subsystem where the socket buffer management code fails to properly validate input parameters when processing specific socket control messages, creating a pathway for unauthorized access to kernel memory structures.
The technical exploitation of this vulnerability occurs through crafted system calls that manipulate the SCM_TIMESTAMPING_OPT_STATS functionality. When local users submit malformed socket control messages to the kernel, the underlying implementation in net/core/skbuff.c and net/socket.c fails to perform adequate bounds checking on array indices or buffer sizes. This results in out-of-bounds memory reads that can expose sensitive kernel data structures to user-space processes, potentially revealing confidential information such as kernel memory layout details, internal socket state information, or other privileged data that should remain inaccessible to unprivileged users. The vulnerability specifically targets the socket buffer management code where the kernel processes timestamping requests, making it particularly dangerous for systems that rely heavily on network monitoring and timing features.
From an operational perspective, this vulnerability presents a significant risk to system security and stability. Local attackers can leverage this flaw to either extract sensitive kernel information that could aid in further exploitation attempts or to cause system instability through denial of service conditions. The out-of-bounds read behavior can lead to kernel crashes, system hangs, or unpredictable behavior that may allow attackers to escalate privileges or gain unauthorized access to system resources. The impact extends beyond simple information disclosure since the vulnerability can be used as a stepping stone for more sophisticated attacks, potentially enabling privilege escalation or persistent access to compromised systems. The fact that this affects the core networking stack makes it particularly dangerous for servers and network infrastructure components that handle high volumes of socket operations.
The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions in software implementations, and relates to ATT&CK technique T1068, which covers local privilege escalation through kernel exploits. Organizations should prioritize immediate patching of affected systems to address this vulnerability, as the kernel versions through 4.10.6 remain vulnerable. The recommended mitigation strategy involves applying the official kernel patches that correct the bounds checking logic in the socket buffer management code and implementing proper input validation for socket control message parameters. Additionally, system administrators should consider monitoring for suspicious socket operations and network traffic patterns that might indicate exploitation attempts. The fix typically involves adding proper bounds checking mechanisms to prevent the out-of-bounds memory accesses that occur when processing SCM_TIMESTAMPING_OPT_STATS requests, ensuring that all array indices and buffer operations remain within valid memory boundaries.