For the S7-300 family that uses external MMC cards (most 31xC CPUs), the password can sometimes be bypassed via direct card reading.
If you have the original project file (the .wld or .s7p file) but simply lost the typed password, you cannot recover the password string. However, you can . unlock s7300 plc password work
Siemens S7-300 CPUs use standard security tiers within the STEP 7 or TIA Portal software environments. These tiers control access to the code and hardware configuration. For the S7-300 family that uses external MMC