: Some third-party "POU Unlock" tools claim to bypass protection levels for specific blocks (POUs) within a project. Password Level 4
This is the most likely reason for the search term. Third-party developers created tools to read the raw binary image of a Siemens MMC card, bypassing the need for a Siemens Prommer.
A common method dating back to the mid-2000s involves creating an image of the MMC and using a recovery tool.
: Passwords reside within system data blocks inside the PLC’s internal EEPROM. SIMATIC S7-300 Security Go to product viewer dialog for this item. simatic s7 200 s7 300 mmc password unlock 2006 09 11
The MMC uses a custom filesystem unrecognized by standard Windows OS. The 2006 Security Disclosures and Password Mechanics
These exploits prove that if a malicious actor has physical access to the PLC or its MMC, logical passwords offer zero protection. Physical lockboxes for automation cabinets are mandatory.
When a user sets a password in STEP 7 to restrict access to the CPU, the password hash is written to the MMC. Because the MMC uses a standard, albeit proprietary, file system structure, directly reading the raw binary data of the card allows access to the password hash. The September 2006 Shift: Direct MMC and EEPROM Reading : Some third-party "POU Unlock" tools claim to
: Software packages hosting legacy exploits often carry embedded trojans, spyware, or keyloggers targeting engineering workstations.
For the S7-300, the password is encrypted and stored on the . By late 2006 and early 2007, tools like Unlock_and_converter_MMC_Image_S7.exe were developed to read this data from a raw disk image.
Independent tools were developed to unlock specific Program Organizational Units (POUs) by modifying system files (like DL200.dll ) within the STEP 7-Micro/WIN environment to bypass password prompts. A common method dating back to the mid-2000s
If you have a binary dump of the MMC (acquired via specific forensic hardware), you can search for the protection block in the hex code and modify the protection level byte from "Level 3" to "Level 1."
Whether you need to on the card or just want to wipe it The software version of STEP 7 or TIA Portal you are using