CVE-2017-10671 in sthttpd
Summary
by MITRE
Heap-based Buffer Overflow in the de_dotdot function in libhttpd.c in sthttpd before 2.27.1 allows remote attackers to cause a denial of service (daemon crash) or possibly have unspecified other impact via a crafted filename.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 07/19/2024
The vulnerability identified as CVE-2017-10671 represents a critical heap-based buffer overflow flaw within the sthttpd web server software. This issue specifically affects the de_dotdot function located in the libhttpd.c source file, which is responsible for processing and sanitizing file paths to prevent directory traversal attacks. The vulnerability exists in sthttpd versions prior to 2.27.1 and presents a significant security risk to systems utilizing this web server implementation. The buffer overflow occurs when the software processes crafted filenames that contain maliciously constructed path sequences designed to exploit memory handling inconsistencies in the directory traversal sanitization routine.
The technical exploitation of this vulnerability leverages improper input validation within the de_dotdot function where the software fails to adequately check the length and composition of incoming filename strings before processing them. When a remote attacker submits a specially crafted filename containing malformed path sequences, the function attempts to manipulate the heap memory structure without proper bounds checking, leading to memory corruption. This heap-based buffer overflow can result in unpredictable behavior including daemon crashes, memory corruption, and potential code execution depending on the system environment and memory layout. The vulnerability falls under CWE-121, heap-based buffer overflow, which is classified as a critical memory safety issue in software development practices. The attack vector requires remote access through HTTP requests and can be executed without authentication, making it particularly dangerous for publicly accessible web servers.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable more sophisticated attacks. While the primary effect manifests as daemon crashes causing service disruption, the underlying memory corruption could theoretically be exploited to achieve arbitrary code execution or information disclosure. Systems running affected sthttpd versions are particularly vulnerable in environments where the web server handles user-provided input through file operations or URL parameters. The vulnerability affects web applications that rely on sthttpd for serving static content or handling file-based operations, creating potential attack surfaces for malicious actors seeking to compromise server availability or escalate privileges. Organizations utilizing embedded systems, IoT devices, or appliances that incorporate sthttpd as their web server component face heightened risk, as these systems often lack regular update mechanisms and may remain vulnerable for extended periods. This vulnerability aligns with ATT&CK technique T1499.004 for network denial of service and could potentially map to T1059 for command execution if exploitation extends beyond simple service disruption.
Mitigation strategies for CVE-2017-10671 primarily focus on immediate software updates to sthttpd version 2.27.1 or later, which includes patches addressing the buffer overflow conditions in the de_dotdot function. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive updates promptly, particularly in critical infrastructure environments. Network segmentation and access controls should be enforced to limit exposure of vulnerable systems to untrusted networks, while monitoring systems should be configured to detect unusual traffic patterns that might indicate exploitation attempts. Input validation measures should be implemented at multiple layers including web application firewalls and application-level sanitization routines to provide defense-in-depth protection. Security teams should conduct thorough vulnerability assessments to identify all systems running affected sthttpd versions and prioritize remediation efforts based on risk exposure. Additionally, implementing intrusion detection systems capable of recognizing patterns associated with directory traversal attacks can provide early warning capabilities for potential exploitation attempts. The vulnerability underscores the importance of regular security maintenance and the need for robust input validation practices in web server implementations to prevent similar memory corruption issues from compromising system integrity and availability.