proxychains only won't work with Firefox, help

[CodexJ]

Hi, I installed proxychains with tor and it works properly with curl or bash and anything else except Firefox it seems it just bypasses proxychians, I searched a lot but i couldn't fix it, help me please.

Firefox will open but stuck here i even checked my ip but it didn't change. Here is my config

# proxychains.conf  VER 4.x
#
#        HTTP, SOCKS4a, SOCKS5 tunneling proxifier with DNS.


# The option below identifies how the ProxyList is treated.
# only one option should be uncommented at time,
# otherwise the last appearing option will be accepted
#
dynamic_chain
#
# Dynamic - Each connection will be done via chained proxies
# all proxies chained in the order as they appear in the list
# at least one proxy must be online to play in chain
# (dead proxies are skipped)
# otherwise EINTR is returned to the app
#
#strict_chain
#
# Strict - Each connection will be done via chained proxies
# all proxies chained in the order as they appear in the list
# all proxies must be online to play in chain
# otherwise EINTR is returned to the app
#
#round_robin_chain
#
# Round Robin - Each connection will be done via chained proxies
# of chain_len length
# all proxies chained in the order as they appear in the list
# at least one proxy must be online to play in chain
# (dead proxies are skipped).
# the start of the current proxy chain is the proxy after the last
# proxy in the previously invoked proxy chain.
# if the end of the proxy chain is reached while looking for proxies
# start at the beginning again.
# otherwise EINTR is returned to the app
# These semantics are not guaranteed in a multithreaded environment.
#
#random_chain
#
# Random - Each connection will be done via random proxy
# (or proxy chain, see  chain_len) from the list.
# this option is good to test your IDS :)

# Make sense only if random_chain or round_robin_chain
#chain_len = 2

# Quiet mode (no output from library)
#quiet_mode

## Proxy DNS requests - no leak for DNS data
# (disable all of the 3 items below to not proxy your DNS requests)

# method 1. this uses the proxychains4 style method to do remote dns:
# a thread is spawned that serves DNS requests and hands down an ip
# assigned from an internal list (via remote_dns_subnet).
# this is the easiest (setup-wise) and fastest method, however on
# systems with buggy libcs and very complex software like webbrowsers
# this might not work and/or cause crashes.
proxy_dns

# method 2. use the old proxyresolv script to proxy DNS requests
# in proxychains 3.1 style. requires `proxyresolv` in $PATH
# plus a dynamically linked `dig` binary.
# this is a lot slower than `proxy_dns`, doesn't support .onion URLs,
# but might be more compatible with complex software like webbrowsers.
#proxy_dns_old

# method 3. use proxychains4-daemon process to serve remote DNS requests.
# this is similar to the threaded `proxy_dns` method, however it requires
# that proxychains4-daemon is already running on the specified address.
# on the plus side it doesn't do malloc/threads so it should be quite
# compatible with complex, async-unsafe software.
# note that if you don't start proxychains4-daemon before using this,
# the process will simply hang.
#proxy_dns_daemon 127.0.0.1:1053

# set the class A subnet number to use for the internal remote DNS mapping
# we use the reserved 224.x.x.x range by default,
# if the proxified app does a DNS request, we will return an IP from that range.
# on further accesses to this ip we will send the saved DNS name to the proxy.
# in case some control-freak app checks the returned ip, and denies to 
# connect, you can use another subnet, e.g. 10.x.x.x or 127.x.x.x.
# of course you should make sure that the proxified app does not need
# *real* access to this subnet. 
# i.e. dont use the same subnet then in the localnet section
#remote_dns_subnet 127 
#remote_dns_subnet 10
remote_dns_subnet 224

# Some timeouts in milliseconds
tcp_read_time_out 15000
tcp_connect_time_out 8000

### Examples for localnet exclusion
## localnet ranges will *not* use a proxy to connect.
## note that localnet works only when plain IP addresses are passed to the app,
## the hostname resolves via /etc/hosts, or proxy_dns is disabled or proxy_dns_old used.

## Exclude connections to 192.168.1.0/24 with port 80
# localnet 192.168.1.0:80/255.255.255.0

## Exclude connections to 192.168.100.0/24
# localnet 192.168.100.0/255.255.255.0

## Exclude connections to ANYwhere with port 80
# localnet 0.0.0.0:80/0.0.0.0
# localnet [::]:80/0

## RFC6890 Loopback address range
## if you enable this, you have to make sure remote_dns_subnet is not 127
## you'll need to enable it if you want to use an application that 
## connects to localhost.
# localnet 127.0.0.0/255.0.0.0
# localnet ::1/128

## RFC1918 Private Address Ranges
# localnet 10.0.0.0/255.0.0.0
# localnet 172.16.0.0/255.240.0.0
# localnet 192.168.0.0/255.255.0.0

### Examples for dnat
## Trying to proxy connections to destinations which are dnatted,
## will result in proxying connections to the new given destinations.
## Whenever I connect to 1.1.1.1 on port 1234 actually connect to 1.1.1.2 on port 443
# dnat 1.1.1.1:1234  1.1.1.2:443

## Whenever I connect to 1.1.1.1 on port 443 actually connect to 1.1.1.2 on port 443
## (no need to write :443 again)
# dnat 1.1.1.2:443  1.1.1.2

## No matter what port I connect to on 1.1.1.1 port actually connect to 1.1.1.2 on port 443
# dnat 1.1.1.1  1.1.1.2:443

## Always, instead of connecting to 1.1.1.1, connect to 1.1.1.2
# dnat 1.1.1.1  1.1.1.2

# ProxyList format
#       type  ip  port [user pass]
#       (values separated by 'tab' or 'blank')
#
#       only numeric ipv4 addresses are valid
#
#
#        Examples:
#
#            	socks5	192.168.67.78	1080	lamer	secret
#		http	192.168.89.3	8080	justu	hidden
#	 	socks4	192.168.1.49	1080
#	        http	192.168.39.93	8080	
#		
#
#       proxy types: http, socks4, socks5, raw
#         * raw: The traffic is simply forwarded to the proxy without modification.
#        ( auth types supported: "basic"-http  "user/pass"-socks )
#
[ProxyList]
# add proxy here ...
# meanwile
# defaults set to "tor"
#socks4 	127.0.0.1 9050
socks5	127.0.0.1 9050

[rofl0r]

your config seems to contain duplicates. also, try proxy_dns_daemon mode

[CodexJ]

I tried it, didn't work, this problem is just with Firefox

[rofl0r]

i suspect your distro uses some sort of firefox launcher that unsets LD_PRELOAD as some sort of security thing. you can try which firefox file $(which firefox) and look into the file with a text editor to figure out what it does.

[CodexJ]

I'm using Ubuntu 22.04.1 LTS, even i reinstalled it and tried again which firefox: /snap/bin/firefox file $(which firefox): /snap/bin/firefox: symbolic link to /usr/bin/snap

[rofl0r]

from https://ubuntu.com/blog/apps-to-snaps

Snaps are secure, isolated from each other and the host system using technologies such as AppArmor, they are cross-platform, and they are self-contained, allowing a developer to package the exact software their application needs. This sandboxed isolation also improves security and allows applications, and whole snap-based systems, to be rolled back should an issue occur.

tl;dr - "snap" applications are using a sandboxed virtual filesystem, so it's not possible to inject host stuff into it, unless you "hack" the snap and embed proxychains directly into the "pack".

solution - get a native/non-snap version of firefox, or if that's not possible, instruct the isolated firefox via its network configuration to use a proxy like tinyproxy or microsocks on localhost, which you run through proxychains, so all connections done by the proxy server software run through the usual proxychains proxy chain.

[CodexJ]

I installed Firefox by apt and i got this error :

parsa@ubuntu:~$ proxychains firefox
[proxychains] config file found: /etc/proxychains4.conf
[proxychains] preloading /usr/lib/x86_64-linux-gnu/libproxychains.so.4
[proxychains] DLL init: proxychains-ng 4.16
[proxychains] DLL init: proxychains-ng 4.16
couldnt read configuration file: Permission denied

but with firefox-esr installed by apt worked ! Thanks.