The module is fuzzing UEFI Variable interface. The module is using UEFI SetVariable interface to write new UEFI variables to SPI flash NVRAM with randomized name/attributes/GUID/data/size. Note: this module modifies contents of non-volatile SPI flash memory (UEFI Variable NVRAM). This may render system unbootable if firmware doesn’t properly handle variable update/delete operations.
 
Usage:
    “chipsec_main -m tools.uefi.uefivar_fuzz [-a <options>]“
    
Options:        
    “[-a <test>,<iterations>,<seed>,<test_case>]“
    – “test“        which UEFI variable interface to fuzz “(all, name, guid, attrib, data, size)“
    – “iterations“    number of tests to perform (default = 1000)
    – “seed“        RNG seed to use
    – “test_case“    test case # to skip to (combined with seed, can be used to skip to failing test)
    All module arguments are optional
    
Examples:
>>> chipsec_main.py -m tools.uefi.uefivar_fuzz
>>> chipsec_main.py -m tools.uefi.uefivar_fuzz -a all,100000
>>> chipsec_main.py -m tools.uefi.uefivar_fuzz -a data,1000,123456789
>>> chipsec_main.py -m tools.uefi.uefivar_fuzz -a name,1,123456789,94

https://github.com/chipsec/chipsec/blob/master/chipsec/modules/tools/uefi/uefivar_fuzz.py