Rule Definition
Software featuring inconsistent locking discipline incurs the risk of deadlock. Locking on this or public members is a bad practice because it means the class loses control over the lock. Any other class could use the instance or the public member for synchronization, and impair scalability (best case) or create deadlocks (worst case).

Remediation
Review and refactor the source code.

Violation Code Sample

class Account
{
    decimal balance;


    public void Withdraw(decimal amount)
    {
        lock (this)
        {
            if (amount > balance)
            {
                throw new Exception("Insufficient funds");
            }
            balance -= amount;
        }
    }
}

Fixed Code Sample

public class Account {     private readonly object balanceLock = new object();     private decimal balance;      public Account(decimal initialBalance)     {         balance = initialBalance;     }      public decimal Debit(decimal amount)     {         lock (balanceLock)         {             if (balance >= amount)             {                 Console.WriteLine($"Balance before debit :{balance, 5}");                 Console.WriteLine($"Amount to remove     :{amount, 5}");                 balance = balance - amount;                 Console.WriteLine($"Balance after debit  :{balance, 5}");                 return amount;             }             else             {                 return 0;             }         }     } }

https://docs.microsoft.com/fr-fr/dotnet/csharp/language-reference/keywords/lock-statement CISQ - ASCSMCWE667