Problem with ERR_BAD_SSL_CLIENT_AUTH_CERT on httpd server

Question

I have an application running on httpd server under Centos 8. The Apache server requires user to show vaild certificate and than the ssl variables like DN, CN and SERIAL are passed to the Flask application (than the access verification is run). The app when not vaild cert is given eg user's cert is not in database, should show error page under url "/site/public/failed" with proper info. Problem is that only my cert is passed by Apache and than page loads correctly (My cert is in db), but when my collages (same company, same CA) try to reach it they are flashed with ERR_BAD_SSL_CLIENT_AUTH_CERT and blank page. I assume that even if they will be in db, the Apache wouldn't let them to access app on it. When I check the logs after them try to connect, it looks different than when I am connecting. One thing that I have spotted is their cert is checked only with depth 0 when my goes to depth 2. config:

Listen ip:443
##SSLPassPhraseDialog exec:/usr/libexec/httpd-ssl-pass-dialog
SSLSessionCache         shmcb:/run/httpd/sslcache(512000)
SSLSessionCacheTimeout  300
SSLRandomSeed startup file:/dev/urandom  256
SSLRandomSeed connect builtin
SSLCryptoDevice builtin
##SSLCipherSuite PROFILE=SYSTEM
##SSLCipherSuite  ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256
##SSLCipherSuite ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK
SSLProtocol all -SSLv3 -TLSv1 -TLSv1.1 -TLSv1.3
SSLHonorCipherOrder on
SSLCompression off


WSGIPythonHome /home/path/to/venv
WSGIRestrictStdin Off
WSGIRestrictStdout Off
<VirtualHost ip:443>
        ServerName      app.com
        ErrorLog        /etc/httpd/logs/sshproxy-secure.error_log
        CustomLog       /etc/httpd/logs/sshproxy-secure.access_log ssl_combined

        SSLEngine on
        SSLCertificateFile      /home/path/to/crt.crt
        SSLCertificateKeyFile   /home/path/to/some_key.key
        SSLCACertificateFile /etc/pki/tls/main_ca.crt
        SSLCACertificateFile /path/to/more/ca.crt

        WSGIDaemonProcess sshproxy threads=20 processes=2 python-path=/home/path/to/venv/lib/python3.10/site-packages
        #user=user1 group=group1 threads=5
        #WSGIPythonPath /opt/sshproxy/lib/python2.7/site-packages
        WSGIScriptAlias / /home/path/to/wsgi-script/sshproxy-webserver-wsgi.py
        WSGIScriptReloading On

    <Directory /home/path/to/app>
        WSGIProcessGroup sshproxy
        WSGIApplicationGroup %{GLOBAL}
        Require all granted
    </Directory>

     #<Location />
     #   SSLRequireSSL
        #Require ip 126.16.13.20 126.16.18.
     #</Location>
        SSLVerifyClient optional
        SSLVerifyDepth 5
        SSLOptions +StdEnvVars
</VirtualHost>

Error logs when I connect (I deleted some sensitive data, but I believe its not important part of logs):

[Mon Aug 29 08:36:54.406586 2022] [ssl:debug] [pid 17586:tid 140176105887488] ssl_engine_kernel.c(2330): [client 126.189.244.168:60496] AH02043: SSL virtual host for servername app.com found
[Mon Aug 29 08:36:54.406615 2022] [ssl:debug] [pid 17586:tid 140176105887488] ssl_engine_kernel.c(2330): [client 126.189.244.168:60496] AH02043: SSL virtual host for servername app.com found
[Mon Aug 29 08:36:54.406629 2022] [core:debug] [pid 17586:tid 140176105887488] protocol.c(2314): [client 126.189.244.168:60496] AH03155: select protocol from , choices=h2,http/1.1 for server app.com
[Mon Aug 29 08:36:59.631867 2022] [ssl:debug] [pid 17586:tid 140176105887488] ssl_engine_kernel.c(1751): [client 126.189.244.168:60496] AH02275: Certificate Verification, depth 2, CRL checking mode: none (0) [subject: 
[Mon Aug 29 08:36:59.632161 2022] [ssl:debug] [pid 17586:tid 140176105887488] ssl_engine_kernel.c(1751): [client 126.189.244.168:60496] AH02275: Certificate Verification, depth 1, CRL checking mode: none (0) [subject: 
[Mon Aug 29 08:36:59.632380 2022] [ssl:debug] [pid 17586:tid 140176105887488] ssl_engine_kernel.c(1751): [client 126.189.244.168:60496] AH02275: Certificate Verification, depth 0, CRL checking mode: none (0) [subject: 
[Mon Aug 29 08:36:59.632679 2022] [ssl:debug] [pid 17586:tid 140176105887488] ssl_engine_kernel.c(2246): [client 126.189.244.168:60496] AH02041: Protocol: TLSv1.3, Cipher: TLS_AES_128_GCM_SHA256 (128/128 bits)
[Mon Aug 29 08:36:59.633566 2022] [ssl:debug] [pid 17586:tid 140176105887488] ssl_engine_kernel.c(383): [client 126.189.244.168:60496] AH02034: Initial (No.1) HTTPS request received for child 204 (server domain:443)
[Mon Aug 29 08:36:59.633893 2022] [authz_core:debug] [pid 17586:tid 140176105887488] mod_authz_core.c(820): [client 126.189.244.168:60496] AH01626: authorization result of Require all granted: granted
[Mon Aug 29 08:36:59.633925 2022] [authz_core:debug] [pid 17586:tid 140176105887488] mod_authz_core.c(820): [client 126.189.244.168:60496] AH01626: authorization result of <RequireAny>: granted

Error logs when they connect:

[Tue Aug 30 11:01:41.293387 2022] [ssl:debug] [pid 24609:tid 140421665646336] ssl_engine_kernel.c(2330): [client 126.189.44.235:57122] AH02043: SSL virtual host for app.com
[Tue Aug 30 11:01:41.293496 2022] [ssl:debug] [pid 24609:tid 140421665646336] ssl_engine_kernel.c(2330): [client 126.189.44.235:57122] AH02043: SSL virtual host for app.com
[Tue Aug 30 11:01:41.293519 2022] [core:debug] [pid 24609:tid 140421665646336] protocol.c(2314): [client 126.189.44.235:57122] AH03155: select protocol from , choices=h2,http/1.1 for server
[Tue Aug 30 11:01:41.476727 2022] [ssl:debug] [pid 24609:tid 140421665646336] ssl_engine_kernel.c(1751): [client 126.189.44.235:57122] AH02275: Certificate Verification, depth 0, CRL checking m
[Tue Aug 30 11:01:41.476860 2022] [ssl:info] [pid 24609:tid 140421665646336] [client 126.189.44.235:57122] AH02276: Certificate Verification: Error (66): EE certificate key too weak [subject: e
[Tue Aug 30 11:01:41.476988 2022] [ssl:info] [pid 24609:tid 140421665646336] [client 126.189.44.235:57122] AH02008: SSL library error 1 in handshake (server domain:443)
[Tue Aug 30 11:01:41.477100 2022] [ssl:info] [pid 24609:tid 140421665646336] SSL Library Error: error:1417C086:SSL routines:tls_process_client_certificate:certificate verify failed
[Tue Aug 30 11:01:41.477120 2022] [ssl:info] [pid 24609:tid 140421665646336] [client 126.189.44.235:57122] AH01998: Connection closed to child 194 with abortive shutdown (server napupp19.corpne
[Tue Aug 30 11:01:44.545107 2022] [ssl:info] [pid 24609:tid 140421573326592] [client 126.189.44.235:57125] AH01964: Connection to child 205 established (server domain:443)
[Tue Aug 30 11:01:44.545572 2022] [socache_shmcb:debug] [pid 24609:tid 140421573326592] mod_socache_shmcb.c(532): AH00835: socache_shmcb_retrieve (0xea -> subcache 10)
[Tue Aug 30 11:01:44.545621 2022] [socache_shmcb:debug] [pid 24609:tid 140421573326592] mod_socache_shmcb.c(917): AH00851: shmcb_subcache_retrieve found no match
[Tue Aug 30 11:01:44.545634 2022] [socache_shmcb:debug] [pid 24609:tid 140421573326592] mod_socache_shmcb.c(542): AH00836: leaving socache_shmcb_retrieve successfully

I don't know what's the reason why their cert is checked starting at depth 0, while mine is from depth 2?

Answer 1

Changing cipher string = default@seclevel=2 to cipher string = default@seclevel=1 in openssl.cnf file has resolved problem. Nonetheless I don't know why my cert was passed while others didn't. We all have standardized token with cert, so they all should have similar sec level.