CVE-2018-7440 in Leptonica
Summary
by MITRE
An issue was discovered in Leptonica through 1.75.3. The gplotMakeOutput function allows command injection via a $(command) approach in the gplot rootname argument. This issue exists because of an incomplete fix for CVE-2018-3836.
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Analysis
by VulDB Data Team • 02/10/2023
The vulnerability identified as CVE-2018-7440 represents a critical command injection flaw within the Leptonica library version 1.75.3 and earlier. This issue affects the gplotMakeOutput function which processes graphical plot outputs and accepts user-supplied rootname arguments that can contain shell command sequences. The vulnerability arises from an incomplete remediation of a previously addressed flaw, specifically CVE-2018-3836, which demonstrates a pattern of recurring security gaps in the library's input validation mechanisms. The root cause stems from inadequate sanitization of user-provided data before it is processed by shell execution functions, creating an environment where malicious payloads can be executed with the privileges of the affected application.
Technical exploitation of this vulnerability occurs when an attacker provides a specially crafted rootname argument containing command substitution syntax using the $(command) pattern. The gplotMakeOutput function processes this input without proper validation or sanitization, allowing the shell to interpret and execute arbitrary commands embedded within the argument. This type of vulnerability maps directly to CWE-78, which specifically addresses OS command injection flaws in software systems. The vulnerability exists in the context of graphical plotting functionality where user inputs are not properly escaped or validated before being passed to system-level shell commands, creating a direct pathway for privilege escalation and system compromise.
The operational impact of CVE-2018-7440 extends beyond simple command execution, as it can enable attackers to perform comprehensive system reconnaissance, data exfiltration, and persistent access establishment. When applications utilizing Leptonica libraries process untrusted input through the gplotMakeOutput function, they become vulnerable to remote code execution attacks that can result in complete system compromise. The vulnerability affects any software that relies on the affected Leptonica versions, including document processing systems, image analysis applications, and automated reporting tools. This creates a widespread attack surface where a single vulnerable component can compromise entire applications and their underlying infrastructure, making it particularly dangerous in enterprise environments where these libraries are commonly integrated.
Mitigation strategies for CVE-2018-7440 require immediate implementation of input validation and sanitization measures to prevent command injection attempts. Organizations should upgrade to Leptonica version 1.76.0 or later where the vulnerability has been properly addressed through comprehensive input validation mechanisms. System administrators should implement proper privilege separation and sandboxing for applications that utilize the affected library functions. Network-level controls including firewall rules and intrusion detection systems can help monitor for suspicious command execution patterns. The ATT&CK framework categorizes this vulnerability under T1059.001 for command and script injection, emphasizing the need for defensive measures that focus on preventing shell command execution from untrusted inputs. Additionally, developers should adopt secure coding practices that avoid direct shell command execution with user-supplied data and implement proper input filtering mechanisms to prevent similar vulnerabilities in future development cycles.