CVE-2018-20752 in Recon-ng
Summary
by MITRE
An issue was discovered in Recon-ng before 4.9.5. Lack of validation in the modules/reporting/csv.py file allows CSV injection. More specifically, when a Twitter user possesses an Excel macro for a username, it will not be properly sanitized when exported to a CSV file. This can result in remote code execution for the attacker.
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Analysis
by VulDB Data Team • 07/04/2023
The vulnerability identified as CVE-2018-20752 represents a critical CSV injection flaw in the Recon-ng reconnaissance framework version 4.9.4 and earlier. This vulnerability resides within the modules/reporting/csv.py file where insufficient input validation permits malicious data to be processed and exported to CSV format without proper sanitization. The flaw specifically affects how Twitter usernames containing Excel macro commands are handled during export operations, creating a pathway for attackers to exploit the system through crafted input data.
The technical implementation of this vulnerability stems from inadequate data sanitization practices within the CSV export functionality. When Recon-ng processes user data for export to CSV format, it fails to properly escape or sanitize special characters that could be interpreted as Excel formulas or macros. This particular weakness allows attackers to inject malicious commands that execute when the CSV file is opened in spreadsheet applications like Microsoft Excel. The vulnerability specifically targets the handling of Twitter usernames where an attacker can craft a username containing a formula prefix such as equals sign followed by a command that would execute upon CSV file opening.
The operational impact of this vulnerability extends beyond simple data corruption or display issues. The potential for remote code execution makes this a severe security concern that could compromise entire systems. When victims open the malicious CSV file in Excel or similar spreadsheet applications, the embedded commands execute automatically, potentially leading to full system compromise. This attack vector aligns with the common technique of leveraging spreadsheet applications as attack surfaces, where CSV injection vulnerabilities are frequently exploited to deliver malicious payloads through social engineering.
This vulnerability maps to CWE-1236, which specifically addresses the lack of sanitization of user-controlled data in CSV export functionality. The attack pattern follows the methodology outlined in the ATT&CK framework under T1059.006 for execution through Microsoft Office applications, where adversaries leverage the trust users place in spreadsheet applications to execute malicious code. The vulnerability demonstrates how seemingly benign data processing functions can become attack vectors when proper input validation and sanitization are omitted from security considerations.
The recommended mitigations for this vulnerability include updating to Recon-ng version 4.9.5 or later where the CSV injection flaw has been addressed through proper input validation and sanitization. Organizations should also implement additional security controls such as restricting the ability to export potentially malicious data, implementing network segmentation to limit access to reconnaissance tools, and conducting regular security assessments of third-party tools used in offensive security operations. Additionally, users should be educated about the risks of opening untrusted CSV files in spreadsheet applications and the importance of verifying data sources before processing potentially malicious content.