CVE-2013-5019 in Ultra Mini HTTPD
Summary
by MITRE
Stack-based buffer overflow in Ultra Mini HTTPD 1.21 allows remote attackers to execute arbitrary code via a long resource name in an HTTP request.
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Analysis
by VulDB Data Team • 07/04/2025
The vulnerability identified as CVE-2013-5019 represents a critical stack-based buffer overflow flaw within Ultra Mini HTTPD version 1.21, a lightweight web server implementation that has been widely deployed in embedded systems and IoT devices. This vulnerability arises from insufficient input validation mechanisms within the HTTP request processing pipeline, specifically when handling resource names in HTTP requests. The flaw manifests when an attacker crafts a malicious HTTP request containing an excessively long resource name that exceeds the allocated stack buffer space, leading to memory corruption that can be exploited to execute arbitrary code on the affected system.
The technical nature of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations on the stack. In the context of Ultra Mini HTTPD 1.21, the HTTP request parsing logic fails to properly validate the length of the resource name component within the request line, allowing an attacker to overflow the predetermined stack buffer size. This overflow can overwrite return addresses, saved registers, and other critical stack data, enabling attackers to redirect program execution flow and inject malicious code. The vulnerability operates at the application layer and requires no authentication to exploit, making it particularly dangerous in environments where the web server is accessible to unauthenticated users.
The operational impact of CVE-2013-5019 extends beyond simple code execution, as it can enable full system compromise in environments where the affected web server runs with elevated privileges. Attackers can leverage this vulnerability to gain unauthorized access to embedded devices, potentially leading to complete system takeover, data exfiltration, or use of compromised devices as part of botnet operations. The vulnerability affects a wide range of devices including routers, network appliances, and IoT gadgets that utilize this particular web server implementation, creating a significant attack surface across multiple industries. The remote exploitation capability means that attackers can target vulnerable systems from anywhere on the network, without requiring physical access or local network presence.
Mitigation strategies for this vulnerability should prioritize immediate software updates and patches from the vendor, as the most effective solution involves upgrading to a patched version of Ultra Mini HTTPD that implements proper input validation and buffer size checking. Organizations should also implement network segmentation and access controls to limit exposure of affected systems, particularly in critical infrastructure environments where these devices are commonly deployed. Additional protective measures include deploying web application firewalls to detect and block malicious HTTP requests, implementing intrusion detection systems to monitor for exploitation attempts, and conducting comprehensive vulnerability assessments to identify all instances of the affected software within the network. The ATT&CK framework categorizes this vulnerability under T1210 - Exploitation of Remote Services, emphasizing the need for robust network security controls to prevent unauthorized access to vulnerable services.