CVE-2019-5065 in Blynk-Library
Summary
by MITRE
An exploitable information disclosure vulnerability exists in the packet-parsing functionality of Blynk-Library v0.6.1. A specially crafted packet can cause an unterminated strncpy, resulting in information disclosure. An attacker can send a packet to trigger this vulnerability.
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Analysis
by VulDB Data Team • 12/13/2023
The vulnerability identified as CVE-2019-5065 represents a critical information disclosure flaw within the Blynk-Library version 0.6.1 packet parsing mechanism. This vulnerability resides in the core communication handling functionality that processes incoming data packets from clients to the Blynk server infrastructure. The Blynk ecosystem is widely used for IoT device management and communication, making this vulnerability particularly concerning as it affects the fundamental data processing capabilities of the library. The flaw manifests when the library encounters specially crafted malicious packets that exploit improper buffer handling during string operations.
The technical root cause of this vulnerability stems from an unterminated strncpy operation within the packet parsing code. When processing incoming packets, the library uses strncpy to copy data into buffers without ensuring proper null termination of the resulting string. This classic buffer overflow pattern creates a situation where adjacent memory locations may contain sensitive data that gets exposed through the malformed packet processing. The strncpy function, while designed to prevent buffer overflows by limiting the number of characters copied, fails to null-terminate the destination string when the source string length equals the specified limit, creating a scenario where information disclosure occurs through memory leaks. This vulnerability directly maps to CWE-121, which addresses stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow conditions, though the specific manifestation here is through information disclosure rather than code execution.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially expose sensitive data from the memory space of the affected system. Attackers can craft specific packets that trigger the unterminated strncpy condition, causing the system to leak memory contents that may include authentication tokens, session identifiers, device credentials, or other confidential information. This information leakage could enable attackers to establish persistent access to IoT devices managed through the Blynk platform, potentially leading to complete compromise of the connected device ecosystem. The vulnerability's exploitability is relatively straightforward as it requires only the ability to send specially crafted packets to the target system, making it particularly dangerous in environments where the Blynk library is used for critical device management operations. According to ATT&CK framework, this vulnerability aligns with T1005 - Data from Local System and T1041 - Exfiltration Over C2 Channel, as it enables unauthorized data extraction from the compromised system.
Mitigation strategies for CVE-2019-5065 should focus on immediate patching of the Blynk-Library to version 0.6.2 or later, which contains the necessary fixes for the unterminated strncpy issue. Organizations should also implement network-level controls such as packet filtering and intrusion detection systems to monitor for suspicious packet patterns that may indicate exploitation attempts. Additionally, regular security assessments of IoT device configurations and network traffic should be conducted to identify any potential compromise indicators. The vulnerability highlights the importance of proper input validation and memory management practices in embedded systems, particularly when handling untrusted data from network sources. Security teams should also consider implementing network segmentation and access controls to limit the potential impact of successful exploitation attempts, as the vulnerability could potentially lead to broader network compromise when combined with other attack vectors.