GUID / UUID
The four-bit M and the 1- to 3-bit N fields code the format of the UUID itself.
|1||based on time, or clock sequence|
|2||reserved in the RFC 4122, but ommitted in many implementations|
|3||based on a MD5 hash|
|5||based on a SHA1 hash|
- intruder-io/guidtool - A tool to inspect and attack version 1 GUIDs
$ guidtool -i 95f6e264-bb00-11ec-8833-00155d01ef00 UUID version: 1 UUID time: 2022-04-13 08:06:13.202186 UUID timestamp: 138691299732021860 UUID node: 91754721024 UUID MAC address: 00:15:5d:01:ef:00 UUID clock sequence: 2099 $ guidtool 1b2d78d0-47cf-11ec-8d62-0ff591f2a37c -t '2021-11-17 18:03:17' -p 10000
Mongo ObjectIds are generated in a predictable manner, the 12-byte ObjectId value consists of: * Timestamp (4 bytes): Represents the ObjectId’s creation time, measured in seconds since the Unix epoch (January 1, 1970). * Machine Identifier (3 bytes): Identifies the machine on which the ObjectId was generated. Typically derived from the machine's hostname or IP address, making it predictable for documents created on the same machine. * Process ID (2 bytes): Identifies the process that generated the ObjectId. Typically the process ID of the MongoDB server process, making it predictable for documents created by the same process. * Counter (3 bytes): A unique counter value that is incremented for each new ObjectId generated. Initialized to a random value when the process starts, but subsequent values are predictable as they are generated in sequence.
- andresriancho/mongo-objectid-predict - Predict Mongo ObjectIds
- In GUID We Trust - Daniel Thatcher - October 11, 2022
- IDOR through MongoDB Object IDs Prediction - Amey Anekar - August 25, 2020