2FAuth Group Management Vulnerabilities Report

Date: January 20, 2025
Version Tested: 5.4.3
Author: @bugdisclose

Overview

During security testing of the 2FAuth application's group management functionality, multiple critical race conditions and data corruption vulnerabilities were identified. These vulnerabilities could lead to data inconsistency, unauthorized access, and potential service disruption.

Run attached script for complete poc

Vulnerabilities

1. Group Deletion Race Condition (CWE-362)

Description

The application fails to properly handle concurrent group deletion operations, leading to orphaned accounts and data inconsistency.

Technical Details

• When a group is deleted while other operations (like account assignment) are pending, the application fails to properly handle the race condition
• Subsequent operations fail with 404 errors but don't properly clean up related data
• Error:

[*] Delete/recreate operation: Status=404, Response=Failed to recreate group
[*] Assign operation: Status=404, Response={"message":"not found"}

Impact

• Severity: High
• CVSS Score: 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H)
• Data corruption leading to orphaned accounts
• Inconsistent application state
• Potential denial of service for affected accounts

2. Foreign Key Constraint Race Condition (CWE-362)

Description

The application attempts to update account references to deleted groups without proper transaction handling, leading to database integrity violations.

Technical Details

• When accounts are being assigned to a group that is concurrently deleted, the application encounters foreign key constraint violations
• The error is not properly handled, leading to inconsistent states
• Error:

SQLSTATE[23000]: Integrity constraint violation: 19 FOREIGN KEY constraint failed 
(Connection: sqlite, SQL: update "twofaccounts" set "group_id" = 24, "updated_at" = ...)

Impact

• Severity: High
• CVSS Score: 7.2 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L)
• Database integrity violations
• Potential data loss or corruption
• Inconsistent group membership states

3. Group Recreation ID Mismatch (CWE-668)

Description

The application allows recreation of deleted groups with new IDs while old references may still exist, leading to confused deputy problems.

Technical Details

• When a group is recreated after deletion, it gets a new ID
• Old accounts may still reference the previous group ID
• Output:

[*] Delete/recreate operation: Status=201, Response=Group recreated: {"id":27,"name":"TestGroup1737336471","twofaccounts_count":0}

Impact

• Severity: Medium
• CVSS Score: 6.5 (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N)
• Orphaned account references
• Potential unauthorized access to recreated groups
• Inconsistent group membership counts

Proof of Concept

A Python script demonstrating these vulnerabilities has been created: group_vuln_poc.py. The script:

1. Creates test accounts and groups
2. Executes concurrent group operations to trigger race conditions
3. Verifies data corruption and inconsistent states
4. Demonstrates orphaned account references

Recommendations

Short-term Fixes

1. Implement Proper Locking

   DB::transaction(function () use ($groupId, $accountIds) {
       DB::table('groups')->lockForUpdate()->find($groupId);
       // Perform group operations
   });

2. Add Validation Checks

   public function assignAccounts($groupId, $accountIds)
   {
       $group = Group::find($groupId);
       if (!$group) {
           throw new ModelNotFoundException();
       }
       DB::transaction(function () use ($group, $accountIds) {
           // Check if group still exists within transaction
           $group = Group::lockForUpdate()->find($group->id);
           if (!$group) {
               throw new ConflictException("Group was deleted");
           }
           // Proceed with assignment
       });
   }

3. Implement Optimistic Locking

   Schema::table('groups', function (Blueprint $table) {
       $table->integer('version')->default(0);
   });

Long-term Fixes

1. Architecture Changes

   • Implement event-driven architecture for group operations
   • Add proper queueing for long-running group operations
   • Implement proper cleanup jobs for orphaned references

2. Database Changes

   • Add proper foreign key constraints with CASCADE rules
   • Implement audit logging for group operations
   • Add version control for group entities

3. API Changes

   • Implement proper API versioning
   • Add proper status codes and error responses
   • Implement rate limiting for group operations

Timeline

• Discovery Date: January 20, 2025
• Vendor Notification: Done
• Public Disclosure: Pending

References

1. CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
2. CWE-668: Exposure of Resource to Wrong Sphere
3. OWASP Top 10 2021: A01 Broken Access Control