Synology recovery password

When the DSM is in pre-configure or recovery mode it is possible to access the command line via telnet using a backdoor admin account.  The account uses a fixed passphrase in pre-configure mode and a dynamic passphrase in recovery mode.

Pre-Configure

Telnet port #23

User: root or admin

Pass: 101-0101

Recovery Mode

Telnet port #23

User: root or admin

Pass: dynamic

• 1st character = month in hexadecimal, lower case (1=Jan, … , a=Oct, b=Nov, c=Dec)
• 2-3 = month in decimal, zero padded and starting in 1 (01, 02, 03, …, 11, 12)
• 4 = dash
• 5-6 = day of the month in hex (01, 02 .., 0A, .., 1F)
• 7-8 = greatest common divisor between month and day, zero padded. This is always a number between 01 and 12.  greatest common divisor is the highest integer number that both operands can be wholly  divided by.

Example

28th October = a10-1c02

15th October = a10-0f05