CVE-2022-42965: Snowflake-connector-python DoS Vulnerability

CVE-2022-42965 Overview

An exponential Regular Expression Denial of Service (ReDoS) vulnerability exists in the snowflake-connector-python PyPI package. This vulnerability can be triggered when an attacker is able to supply arbitrary input to the undocumented get_file_transfer_type method. The exponential time complexity of the regular expression pattern matching can cause severe performance degradation and resource exhaustion, potentially leading to denial of service conditions.

Critical Impact
Attackers can exploit this ReDoS vulnerability to cause denial of service by sending specially crafted input strings that trigger catastrophic backtracking in the regex engine, consuming excessive CPU resources and potentially making applications unresponsive.

Affected Products

snowflake snowflake-connector-python

Discovery Timeline

2022-11-09 - CVE CVE-2022-42965 published to NVD
2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-42965

Vulnerability Analysis

This vulnerability is classified as CWE-1333 (Inefficient Regular Expression Complexity). The get_file_transfer_type method in the snowflake-connector-python package contains a regular expression pattern that exhibits exponential time complexity when processing certain malicious input strings. This is a characteristic pattern of ReDoS vulnerabilities where the regex engine's backtracking mechanism can be exploited.

When a carefully crafted input string is provided to the vulnerable method, the regex engine enters a state of catastrophic backtracking. This occurs when the pattern contains nested quantifiers or overlapping alternatives that cause the engine to explore an exponentially growing number of possible matches before ultimately failing. The result is that CPU usage spikes dramatically and the application thread becomes blocked while processing the malicious input.

Root Cause

The root cause of this vulnerability lies in an inefficiently designed regular expression pattern within the get_file_transfer_type method. The pattern likely contains constructs such as nested quantifiers (e.g., (a+)+), overlapping alternatives, or other structures that allow for exponential backtracking behavior. When input strings are designed to nearly match but ultimately fail against such patterns, the regex engine must explore all possible combinations before determining no match exists.

Attack Vector

This vulnerability can be exploited over the network without requiring authentication or user interaction. An attacker who can influence the input passed to the get_file_transfer_type method can craft malicious strings that trigger the exponential backtracking behavior. The attack does not require any privileges and targets the availability of the system.

The exploitation scenario typically involves:

Identifying an application endpoint that processes user-controlled input through the vulnerable method
Crafting a string with repeating characters that nearly match the vulnerable regex pattern
Submitting the malicious input to cause CPU exhaustion on the target system

The vulnerable method being undocumented suggests it may be called internally by other documented functions, potentially expanding the attack surface beyond direct method invocation. For detailed technical analysis, see the JFrog Vulnerability Analysis.

Detection Methods for CVE-2022-42965

Indicators of Compromise

Abnormally high CPU utilization on systems running Python applications using snowflake-connector-python
Application threads becoming unresponsive or timing out during file transfer operations
Increased response times or service degradation in Snowflake data pipeline applications
Python process memory and CPU consumption spikes correlating with incoming requests

Detection Strategies

Monitor application performance metrics for unusual CPU utilization patterns in Python worker processes
Implement request timeout monitoring for operations involving the Snowflake connector
Deploy application performance monitoring (APM) to detect slow method execution in snowflake-connector-python components
Analyze access logs for unusually long or repetitive input strings targeting file transfer functionality

Monitoring Recommendations

Configure alerting for sustained high CPU usage on servers running Snowflake connector applications
Implement request duration monitoring with thresholds appropriate for normal file transfer operations
Deploy endpoint detection solutions to identify patterns consistent with ReDoS exploitation attempts
Enable detailed logging for Snowflake connector operations to facilitate forensic analysis

How to Mitigate CVE-2022-42965

Immediate Actions Required

Audit applications using snowflake-connector-python to identify potential exposure to the vulnerable method
Implement input validation and length restrictions on user-controlled input before processing
Configure request timeouts to prevent single requests from consuming resources indefinitely
Update snowflake-connector-python to the latest available version that addresses this vulnerability

Patch Information

Organizations should update the snowflake-connector-python package to the latest version available from PyPI. Review the JFrog Vulnerability Analysis for specific version information and remediation guidance. Use pip list --outdated to check the currently installed version and pip install --upgrade snowflake-connector-python to update to the latest release.

Workarounds

Implement input length restrictions to prevent excessively long strings from reaching the vulnerable method
Add request timeout configurations at the application and web server levels to limit resource consumption
Deploy a Web Application Firewall (WAF) with rules to detect and block potential ReDoS attack patterns
Isolate Snowflake connector operations in separate processes or containers to limit blast radius of DoS attacks

bash

# Configuration example
# Upgrade snowflake-connector-python to latest version
pip install --upgrade snowflake-connector-python

# Verify installed version
pip show snowflake-connector-python

# Implement request timeout in application configuration (example for common frameworks)
# For gunicorn workers:
# gunicorn --timeout 30 myapp:app

# For uwsgi:
# uwsgi --http-timeout 30 --harakiri 30