Arbitrary Code Execution in the Universal Turing Machine
This is an implementation of the Universal Turing Machine as presented in Minsky, Computation: Finite and infinite machines, 1967, Chapter 7.
The default input to the simulated machine is an exploit that achieves arbitrary code execution.
Run the program with
$ python3.7 minskys_turing_machine.py
State 19 reading S writing B shifting left resulting in: 00111MYBAAXAAAAAAAXAABAAAAB1000Y01SX0000001X0010110X0100011X0110100Y00 Step 380
A
State 19 reading S writing B shifting left resulting in: 0011M0Y00BX0000000X001000011000Y00SX0000001X0010110X0100011X0110100Y00 Step 721
A
State 19 reading S writing B shifting left resulting in: 001M00Y00BX0000000X001000011000Y00SX0000001X0010110X0100011X0110100Y00 Step 1055
A
State 19 reading S writing B shifting left resulting in: 00M000Y00BX0000000X001000011000Y00SX0000001X0010110X0100011X0110100Y00 Step 1393
A
State 18 reading S writing A shifting left resulting in: 0M0000Y00AX0000000X001000011000Y00SX0000001X0010110X0100011X0110100Y00 Step 1735
A
State 18 reading S writing A shifting left resulting in: M00000Y00AX0000000X001000011000Y00SX0000001X0010110X0100011X0110100Y00 Step 1909
A
Ran out of tape!
Help is provided with
$ python3.7 minskys_turing_machine.py -h
usage: minskys_turing_machine.py [-h] [--machine_condition MACHINE_CONDITION]
[--machine_description MACHINE_DESCRIPTION]
[--machine_tape MACHINE_TAPE]
[--verbosity VERBOSITY]
A Universal Turing Machine as described in Minsky, Computation: Finite and
infinite machines, 1967, Chapter 7.
optional arguments:
-h, --help show this help message and exit
--machine_condition MACHINE_CONDITION
The internal state and the currently read symbol. The
default starts in state 00 and the head is scanning a
1.
--machine_description MACHINE_DESCRIPTION
The program of the Turing machine to be simulated.
--machine_tape MACHINE_TAPE
The simulated Turing machine's initial tape. The
default is an exploit that achieves arbitrary code
execution.
--verbosity VERBOSITY
Degree of vebosity, 1-4.
The vulnerability has been assigned CVE-2021-32471 and is presented in detail in Pontus Johnson's paper Intrinsic Propensity for Vulnerability in Computers? Arbitrary Code Execution in the Universal Turing Machine from 2021. There is also a talk on YouTube on the vulnerability and its exploitation.
A visual simulation of the exploit is available at https://intrinsic-propensity.github.io.
For an alternative re-implementation of the vulnerable Minsky Turing machine, check out Andreas Rozek's specification for Martín Ugarte's Turing machine simulator.