CVE-2017-11670 in eapmd5pass
Summary
by MITRE
A length validation (leading to out-of-bounds read and write) flaw was found in the way eapmd5pass 1.4 handled network traffic in the extract_eapusername function. A remote attacker could potentially use this flaw to crash the eapmd5pass process by generating specially crafted network traffic.
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Analysis
by VulDB Data Team • 11/02/2019
The vulnerability identified as CVE-2017-11670 resides within the eapmd5pass software version 1.4, specifically within the extract_eapusername function that processes network traffic. This flaw represents a classic buffer over-read and potential write condition that occurs when the application fails to properly validate the length of incoming data before processing it. The issue manifests during the handling of Extensible Authentication Protocol messages where the software does not adequately check the boundaries of received data payloads, creating opportunities for malicious actors to manipulate network traffic in ways that can lead to system instability.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the network processing pipeline of eapmd5pass. When network packets containing EAP authentication messages are received, the extract_eapusername function attempts to parse and extract username information without sufficient boundary checks. This allows an attacker to craft specially designed network packets that exceed expected data lengths, causing the application to read or write beyond allocated memory boundaries. The flaw operates at the intersection of network protocol handling and memory management, where the absence of proper length validation creates a direct path for exploitation through crafted network traffic.
From an operational impact perspective, this vulnerability presents a significant risk to systems relying on eapmd5pass for network authentication services. Remote attackers can leverage this flaw to execute denial-of-service attacks against the affected software, potentially causing the process to crash and terminate unexpectedly. The stability of network authentication services could be compromised, leading to service disruption for legitimate users and potentially creating opportunities for more sophisticated attacks. The vulnerability affects the availability aspect of the security triad, as successful exploitation results in service interruption that impacts network access and authentication capabilities.
The vulnerability aligns with CWE-129, which addresses "Improper Validation of Array Index," and demonstrates characteristics consistent with CWE-787, "Out-of-bounds Write," and CWE-125, "Out-of-bounds Read." From an ATT&CK framework perspective, this vulnerability maps to T1499.004, "Endpoint Denial of Service," as it enables remote attackers to cause system instability and service disruption. The attack vector involves network-based exploitation where adversaries craft malicious packets to trigger the buffer overflow conditions, making it particularly dangerous in environments where authentication services are critical to network operations.
Mitigation strategies should focus on implementing proper input validation and boundary checking mechanisms within the extract_eapusername function. System administrators should prioritize updating to patched versions of eapmd5pass where available, as this represents the most effective immediate solution. Network-level protections such as intrusion detection systems can help detect and block malicious traffic patterns associated with this vulnerability. Additionally, implementing proper memory protection mechanisms and bounds checking in the application code will prevent similar issues from occurring in other network processing components. Organizations should also consider network segmentation and access controls to limit the potential impact of successful exploitation attempts.