Multiple vulnerabilities have been found in Cisco RV Series devices that allows an attacker to overwrite/create arbitrary files, execute arbitrary commands, and execute Cross-Site Request Forgery attacks.
These following Cisco RV Series devices are affected by these issues:
- Cisco RV120W Wireless-N VPN Firewall running firmware prior to 184.108.40.206
- Cisco RV180 VPN Router and Cisco RV180W Wireless-N Multifunction VPN Router running firmware versions prior to 220.127.116.11
- Cisco RV220W Wireless Network Security Firewall running any currently available release
- cisco-sa-20141105-rv: Multiple Vulnerabilities in Cisco Small Business RV Series Routers
Please consult Cisco advisory cisco-sa-20141105-rv for fix information.
Multiple vulnerabilities have been found in Cisco RV Series devices that allows an attacker to overwrite/create arbitrary files, execute arbitrary commands, and execute CSRF attacks.
Insecure handling of file uploads
The admin pages of the affected devices are created using LUA scripts. It has been discovered that the affected devices use a cookie named
TeamF1Login in an insecure manner. The cookie value is used as a path name for storing the uploaded file. No input validation is done on the cookie value. Consequently, an attacker can set this to any value and thus create files in arbitrary locations.
It should be noted that:
- the web server (thttpd) runs as
- existing files will be overwritten;
- this issue can be exploited by unauthenticated users.
local function fileupload (filename) -- create a temporary file for uploading the file field --local file, err = tmpfile() -- Adarsh 7/16/07 local filename = mycookieget("TeamF1Login") local file, err = myopen("/tmp/" .. filename, "wb") if file == nil then discardinput(bytesleft) error("Cannot create a temporary file.\n"..err) end local bytesread = 0 local boundaryline = "\r\n"..boundary local out = function (str) local sl = strlen (str) if bytesread + sl > maxfilesize then discardinput (bytesleft) error (format ("Maximum file size (%d kbytes) exceeded while uploading `%s'", maxfilesize / 1024, filename)) end file:write (str) bytesread = bytesread + sl end if readuntil (boundaryline, out) then file:seek ("set", 0) return file, bytesread else error (format ("Error processing multipart/form-data.\nUnexpected end of input while uploading %s", filename)) end end
Command injection in diagnostics tools
The admin pages contain a couple of network diagnostic tools, such as the ability to perform an ICMP ping. Entering special characters in the different forms renders the following error message:
Invalid IP Address/Domain name:Domain/WAN (Internet) must contain only alphanumeric letters, '.' and '-'.
It appears that this check is not enforced server side. Sending the request directly can be used to submit & execute arbitrary commands, which will be executed with root privileges. A valid session is required to access the diagnostics tools.
if (ButtonType and ButtonType == "ping") then local inputTable = web.cgiToLuaTable(cgi) local throughVpn = false local ipToPing = string.sub(inputTable["ping.ip"], string.find(inputTable["ping.ip"], '[%a%d\.:]+')) local pingfile = db.getAttribute("environment", "name", "PING_FILE_NAME", "value") local pingprog = "" if (inputTable["ping.throughVpn"] ~= nil and inputTable["ping.throughVpn"] == "1") then throughVpn = true end -- ping [...] else pingprog = db.getAttribute("environment", "name", "PING_PROGRAM", "value") options1 = " 2>&1 " local cmd_ping = pingprog .. " " .. ipToPing globalCmdOutput = util.runShellCmd(cmd_ping, pingfile, "/tmp/pingErr.txt", options1) STATUS_CLASS = INFO_CLASS statusMessage = (trStrings["11307"] or 'i18nHTMLMissing') .. " " .. ipToPing end end web.goToPage(NextPage, true, true)
GET requests can be used to bypass Referer check
POST request is send to the application, a check is performed on the
Referer header. If the
Referer is empty or contains an external page, an error message is displayed (
401 Unauthorized). It appears that this check is not performed for
POST parameters are interchangeable and since the Referer check is the only measure against Cross-Site Request Forgery (CSRF) attacks, it is possible to execute CSRF attacks using specially crafted URLs. For example the following URL adds an admin account to the user database: