CVE-2020-17407 in Bullet-LTE
Summary
by MITRE • 10/14/2020
This vulnerability allows remote attackers to execute arbitrary code on affected installations of Microhard Bullet-LTE prior to v1.2.0-r1112. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of authentication headers. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-10596.
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Analysis
by VulDB Data Team • 11/19/2020
This vulnerability represents a critical buffer overflow flaw in Microhard Bullet-LTE firmware versions prior to v1.2.0-r1112, classified under CWE-121 as a stack-based buffer overflow condition. The vulnerability stems from insufficient input validation within the authentication header processing mechanism, creating a pathway for remote code execution without requiring any authentication credentials. The flaw specifically manifests when the system handles user-supplied data that exceeds the predetermined buffer size allocated on the stack, allowing malicious input to overwrite adjacent memory locations and potentially corrupt program execution flow.
The technical implementation of this vulnerability involves the improper handling of authentication headers where the firmware fails to validate the length of incoming data before performing memory copy operations. This weakness creates a predictable exploitation scenario where an attacker can craft malicious authentication headers containing oversized payloads that exceed the fixed-length stack buffer capacity. The vulnerability's impact is particularly severe as it allows execution of arbitrary code with root privileges, effectively compromising the entire system's integrity and confidentiality. The absence of authentication requirements means that any remote attacker can exploit this flaw without prior access credentials, making it highly dangerous in networked environments.
From an operational perspective, this vulnerability exposes organizations using Microhard Bullet-LTE devices to significant security risks including complete system compromise, data exfiltration, and potential lateral movement within networked infrastructure. The root privilege execution context means that successful exploitation can provide attackers with unrestricted access to all system resources, network interfaces, and potentially other connected devices. The vulnerability's classification under the ZDI-CAN-10596 identifier confirms its recognition by the cybersecurity community as a serious threat requiring immediate attention and remediation. This type of vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1566 for credential harvesting, as exploitation can lead to further reconnaissance and privilege escalation activities.
The recommended mitigation strategy involves immediate deployment of firmware updates to version 1.2.0-r1112 or later, which contains the necessary patches to address the buffer overflow condition. Network administrators should also implement network segmentation and monitoring to detect unusual authentication header patterns that might indicate exploitation attempts. Additional protective measures include disabling unnecessary services, implementing strict access controls, and conducting comprehensive vulnerability assessments of all networked devices. Organizations should also establish incident response procedures specifically addressing buffer overflow exploits and maintain current threat intelligence feeds to monitor for related exploitation activities targeting similar firmware vulnerabilities.