CVE-2022-1544 in yii-helpers
Summary
by MITRE • 05/01/2022
Formula Injection/CSV Injection due to Improper Neutralization of Formula Elements in CSV File in GitHub repository luyadev/yii-helpers prior to 1.2.1. Successful exploitation can lead to impacts such as client-sided command injection, code execution, or remote ex-filtration of contained confidential data.
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Analysis
by VulDB Data Team • 05/04/2022
The vulnerability identified as CVE-2022-1544 represents a critical formula injection flaw within the luyadev/yii-helpers GitHub repository affecting versions prior to 1.2.1. This issue stems from improper neutralization of formula elements when processing CSV files, creating a dangerous condition where maliciously crafted input can be interpreted as executable commands by spreadsheet applications. The vulnerability specifically targets the handling of data within CSV export functionalities, where user-provided content containing formula elements such as =cmd|/C calc.exe or similar command execution payloads can be embedded directly into the exported files. When these malicious CSV files are opened in spreadsheet applications like Microsoft Excel, Google Sheets, or LibreOffice Calc, the embedded formulas execute automatically, potentially leading to unauthorized command execution on the victim's system.
The technical exploitation of this vulnerability follows a well-established pattern that aligns with CWE-15 (Improper Neutralization of Special Elements) and CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component). Attackers can craft malicious input strings containing spreadsheet formula syntax that, when processed through the affected library's CSV export functionality, gets written directly to output files without proper sanitization. The attack surface becomes particularly dangerous when considering the ATT&CK framework's technique T1059.001 (Command and Scripting Interpreter: PowerShell) and T1059.003 (Command and Scripting Interpreter: Windows Command Shell), as these formula injection payloads can trigger execution of arbitrary commands on the victim's machine. The vulnerability is particularly concerning because CSV files are commonly used for data exchange and are frequently opened in spreadsheet applications, making the attack vector highly accessible and potentially widespread.
The operational impact of CVE-2022-1544 extends beyond simple command execution to encompass potential data exfiltration and system compromise. When an attacker successfully injects a formula into a CSV file, the payload can execute in the context of the user who opens the file, potentially allowing for information disclosure through commands that access system resources or network connections. The vulnerability's severity is amplified by its potential to be leveraged in phishing campaigns or supply chain attacks where malicious actors distribute compromised CSV files through legitimate channels. Organizations using the affected yii-helpers library in applications that generate CSV exports are at risk of having their users' systems compromised when they open these malicious files. The impact is particularly severe in enterprise environments where CSV exports are commonly used for data analysis, reporting, and integration purposes, making the attack surface potentially large and the attack vector highly effective.
Mitigation strategies for CVE-2022-1544 should focus on immediate version upgrades to 1.2.1 or later, which contain the necessary fixes for proper formula element neutralization. Organizations should implement comprehensive input validation and sanitization processes for all data that will be exported to CSV format, particularly ensuring that special characters and formula indicators are properly escaped or removed. The implementation of CSV-specific security measures such as automatic formula disabling in spreadsheet applications or the use of CSV-safe export libraries can provide additional protection layers. Security teams should conduct thorough vulnerability assessments to identify all applications using the affected library and ensure proper patching. Network monitoring should be enhanced to detect potential attempts to distribute malicious CSV files, and user education programs should emphasize the dangers of opening CSV files from untrusted sources. The fix implemented in version 1.2.1 typically involves proper escaping of special characters and the implementation of a whitelist-based approach for CSV content processing, ensuring that formula elements are neutralized before being written to output files.