CVE-2015-4590 in JSON
Summary
by MITRE
The extractFrom function in Internals/QuotedString.cpp in Arduino JSON before 4.5 allows remote attackers to cause a denial of service (crash) via a JSON string with a \ (backslash) followed by a terminator, as demonstrated by "\\\0", which triggers a buffer overflow and over-read.
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Analysis
by VulDB Data Team • 05/21/2022
The vulnerability identified as CVE-2015-4590 represents a critical buffer over-read condition within the Arduino JSON library's quoted string parsing functionality. This issue affects versions prior to 4.5 and stems from improper handling of escape sequences during JSON string extraction operations. The flaw specifically manifests when the extractFrom function processes JSON strings containing a backslash character immediately followed by a null terminator character, creating a scenario where the parser attempts to read beyond allocated memory boundaries.
The technical implementation of this vulnerability resides in the Internals/QuotedString.cpp file where the extractFrom function fails to properly validate escape sequence patterns before attempting to parse quoted strings. When processing malformed input such as the demonstrated "\" sequence, the function does not adequately check bounds before accessing memory locations, leading to unauthorized memory access patterns that result in application crashes and potential system instability. This behavior constitutes a classic buffer over-read vulnerability that can be exploited to cause denial of service conditions.
From an operational perspective, this vulnerability presents significant risks to embedded systems and IoT devices that rely on Arduino JSON libraries for data processing and communication. The remote attack vector allows adversaries to craft malicious JSON payloads that can be transmitted over network connections or injected through various communication channels, making it particularly dangerous in environments where devices process untrusted input from external sources. The crash condition can be repeatedly triggered, leading to persistent service disruption and potential system compromise.
The vulnerability aligns with CWE-125: "Out-of-Bounds Read" and demonstrates characteristics consistent with ATT&CK technique T1499.001: "Endpoint Denial of Service" where attackers exploit software flaws to cause system instability. The impact extends beyond simple denial of service as the over-read behavior may expose sensitive memory contents or provide opportunities for further exploitation through information disclosure mechanisms. Organizations deploying Arduino-based systems should prioritize immediate patching to address this vulnerability.
Mitigation strategies should focus on upgrading to Arduino JSON version 4.5 or later, which includes proper bounds checking and escape sequence validation. Additionally, implementing input validation at network boundaries and employing defensive programming practices such as memory sanitization and bounds verification can reduce the risk of exploitation. Regular security assessments of embedded systems and network devices using vulnerable libraries should be conducted to identify and remediate similar vulnerabilities across the infrastructure.