CVE-2012-4999 in Mr804
Summary
by MITRE
Mercury MR804 Router 8.0 3.8.1 Build 101220 Rel.53006nB allows remote attackers to cause a denial of service (service hang) via a crafted string in HTTP header fields such as (1) If-Modified-Since, (2) If-None-Match, or (3) If-Unmodified-Since. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 07/28/2024
The vulnerability identified as CVE-2012-4999 affects the Mercury MR804 Router version 8.0 3.8.1 Build 101220 Rel.53006nB, representing a critical denial of service weakness that can be exploited remotely by malicious actors. This flaw resides within the router's HTTP header processing mechanism, specifically targeting three distinct header fields that are commonly used for conditional requests in web communications. The affected router fails to properly validate or sanitize input strings within these HTTP headers, creating an opportunity for attackers to craft malicious payloads that trigger system instability.
The technical exploitation of this vulnerability occurs when an attacker sends specially crafted HTTP requests containing malformed strings within the If-Modified-Since, If-None-Match, or If-Unmodified-Since header fields. These headers are typically used by web clients to make conditional requests based on resource modification dates or entity tags, but the Mercury router's implementation lacks proper input validation and error handling mechanisms. When the router processes these malformed strings, the parsing routine becomes unstable, leading to a service hang condition that effectively renders the router non-functional and disrupts network connectivity for all connected devices.
From an operational perspective, this vulnerability presents significant risks to network availability and business continuity, particularly in environments where uninterrupted network services are critical. The remote nature of the attack means that adversaries can exploit this weakness from outside the local network without requiring physical access or authentication credentials. The service hang condition typically results in complete network disruption until manual intervention occurs, requiring administrators to physically access the device or perform a power cycle to restore functionality. This vulnerability directly aligns with CWE-129, which addresses improper validation of input boundaries, and represents a classic example of a buffer overflow or input parsing vulnerability that leads to system instability.
The attack vector for this vulnerability follows established patterns documented in the MITRE ATT&CK framework under the service stop technique, where adversaries target system services to create denial of service conditions. Network administrators should recognize this as a potential indicator of compromise, particularly when observing unexplained network outages or service disruptions. The vulnerability's impact extends beyond simple connectivity issues, as it can be leveraged as a preliminary step in more complex attack chains, potentially enabling further exploitation attempts against the compromised network infrastructure. Organizations should implement network monitoring solutions capable of detecting anomalous HTTP traffic patterns and consider deploying intrusion detection systems to identify and block malicious requests targeting these specific header fields.
Mitigation strategies for CVE-2012-4999 should include immediate firmware updates from the manufacturer, as this vulnerability has been addressed in subsequent releases of the Mercury router software. Network segmentation and access control measures can help limit the potential impact by restricting direct internet access to router management interfaces. Administrators should also implement proper network monitoring to detect unusual traffic patterns and establish incident response procedures for rapid recovery from service disruption events. Additionally, regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other network devices within the infrastructure, ensuring comprehensive protection against similar remote denial of service attacks that may target different components of the network ecosystem.