hrDeviceDescrvalue (OID 22.214.171.124.126.96.36.199.2.1.3, textual description of a device) is demonstrated below:
6870204c617365724a65742034323530is hexadecimal for
hp LaserJet 4250. As can be seen, it is possible to invoke (a subset of) SNMP commands over PJL via PML. A security-sensitive use of PML is to reset HP printers to factory defaults via ordinary print jobs, therefore removing protection mechanisms like user-set passwords.
\x1b), followed by
%-12345X. It was originally introduced with HP's PCL and is supported by most modern laser printers. A good practice of ‘printer drivers’ is to invoke the UEL at the beginning and at the end of each print job, so interpretation of the printer language is stopped/restarted and each job has its own, separate environment as shown below:
0(compare credential disclosure). Since the job server loop is generally responsible for cleaning up the state of the interpreter between jobs, any changes that are made outside the server loop will remain as part of the permanent state of the interpreter for all subsequent jobs. In other words, a print job can access and alter further jobs. Bingo!