CVE-2014-7859 in DNR-320L
Summary
by MITRE
Stack-based buffer overflow in login_mgr.cgi in D-Link firmware DNR-320L and DNS-320LW before 1.04b08, DNR-322L before 2.10 build 03, DNR-326 before 2.10 build 03, and DNS-327L before 1.04b01 allows remote attackers to execute arbitrary code by crafting malformed "Host" and "Referer" header values.
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Analysis
by VulDB Data Team • 12/16/2022
The vulnerability identified as CVE-2014-7859 represents a critical stack-based buffer overflow in the login_mgr.cgi component of several D-Link network storage devices including the DNR-320L, DNS-320LW, DNR-322L, DNR-326, and DNS-327L models. This flaw exists within the firmware implementations of these network attached storage devices, specifically affecting versions prior to the mentioned security patches. The vulnerability stems from inadequate input validation within the web-based management interface, where the application fails to properly sanitize HTTP header values during the authentication process. The affected cgi script processes incoming requests without sufficient bounds checking on the Host and Referer header parameters, creating an exploitable condition that can be leveraged by remote attackers.
The technical exploitation of this vulnerability occurs through the manipulation of HTTP headers in crafted network requests sent to the affected devices. When the login_mgr.cgi script receives malformed Host and Referer header values, it fails to validate the length of these inputs before copying them into fixed-size stack buffers. This improper handling creates a buffer overflow condition where attacker-controlled data can overwrite adjacent memory locations including return addresses and function pointers. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of unsafe string handling in network applications. Attackers can craft malicious HTTP requests containing oversized header values that exceed the allocated buffer space, leading to memory corruption that can be exploited to execute arbitrary code on the target device.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with complete control over the affected network storage devices. Once exploited, attackers can gain unauthorized access to stored data, modify system configurations, install malicious software, or use the compromised devices as entry points for further network penetration. The vulnerability affects devices that are commonly deployed in small office and home environments where network security may be less robust, making them attractive targets for cybercriminals seeking to establish persistent access to network resources. The remote nature of the attack means that exploitation can occur without physical access to the devices, and the vulnerability affects multiple models across different firmware versions, amplifying the potential attack surface. Organizations using these devices face significant risk of data breaches, system compromise, and potential use as botnet nodes for larger-scale attacks.
Mitigation strategies for this vulnerability require immediate firmware updates from D-Link to address the buffer overflow condition in the login_mgr.cgi component. Network administrators should prioritize patching all affected devices with the latest firmware versions that contain proper input validation and bounds checking mechanisms. Additionally, implementing network segmentation and access controls can help limit the potential impact of exploitation by restricting direct internet access to these devices. Security monitoring should include detection of unusual HTTP header patterns that might indicate exploitation attempts, and regular vulnerability assessments should be conducted to identify similar issues in other network components. The remediation process should also involve disabling unnecessary web management interfaces when not actively required, as this reduces the attack surface and potential entry points for attackers. Organizations should consider implementing intrusion detection systems specifically configured to detect malformed HTTP headers that could indicate attempts to exploit this and similar buffer overflow vulnerabilities.