o [NSE] Oops, there was a vulnerability in one of our 437 NSE scripts.

If you ran the (fortunately non-default) http-domino-enum-passwords
  script with the (fortunately also non-default)
  domino-enum-passwords.idpath parameter against a malicious server,
  it could cause an arbitrarily named file to to be written to the
  client system.  Thanks to Trustwave researcher Piotr Duszynski for
  discovering and reporting the problem.  We've fixed that script, and
  also updated several other scripts to use a new
  stdnse.filename_escape function for extra safety.  This breaks our
  record of never having a vulnerability in the 16 years that Nmap has
  existed, but that's still a fairly good run. [David, Fyodor]

CHANGELOG

@@ -19,6 +19,18 @@ o [Ncat] Added --lua-exec. This feature is basically an equivalent of ncat
   redirecting all stdin and stdout operations to the socket connection. 
   [Jacek Wielemborek]
 
+o [NSE] Oops, there was a vulnerability in one of our 437 NSE scripts.
+  If you ran the (fortunately non-default) http-domino-enum-passwords
+  script with the (fortunately also non-default)
+  domino-enum-passwords.idpath parameter against a malicious server,
+  it could cause an arbitrarily named file to to be written to the
+  client system.  Thanks to Trustwave researcher Piotr Duszynski for
+  discovering and reporting the problem.  We've fixed that script, and
+  also updated several other scripts to use a new
+  stdnse.filename_escape function for extra safety.  This breaks our
+  record of never having a vulnerability in the 16 years that Nmap has
+  existed, but that's still a fairly good run. [David, Fyodor]
+
 o [NSE] Added teamspeak2-version.nse by Marin Maržić.
 
 o Nmap's routing table is now sorted first by netmask, then by metric.

nselib/stdnse.lua

@@ -1195,4 +1195,36 @@ function pretty_printer (obj, printer)
   return aux(obj, "")
 end
 
+-- This pattern must match the percent sign '%' since it is used in
+-- escaping.
+local FILESYSTEM_UNSAFE = "[^a-zA-Z0-9._-]"
+---
+-- Escape a string to remove bytes and strings that may have meaning to
+-- a filesystem, such as slashes. All bytes are escaped, except for:
+-- * alphabetic <code>a</code>-<code>z</code> and <code>A</code>-<code>Z</code>, digits 0-9, <code>.</code> <code>_</code> <code>-</code>
+-- In addition, the strings <code>"."</code> and <code>".."</code> have
+-- their characters escaped.
+--
+-- Bytes are escaped by a percent sign followed by the two-digit
+-- hexadecimal representation of the byte value.
+-- * <code>filename_escape("filename.ext") --> "filename.ext"</code>
+-- * <code>filename_escape("input/output") --> "input%2foutput"</code>
+-- * <code>filename_escape(".") --> "%2e"</code>
+-- * <code>filename_escape("..") --> "%2e%2e"</code>
+-- This escaping is somewhat like that of JavaScript
+-- <code>encodeURIComponent</code>, except that fewer bytes are
+-- whitelisted, and it works on bytes, not Unicode characters or UTF-16
+-- code points.
+function filename_escape(s)
+  if s == "." then
+    return "%2e"
+  elseif s == ".." then
+    return "%2e%2e"
+  else
+    return (string.gsub(s, FILESYSTEM_UNSAFE, function (c)
+      return string.format("%%%02x", string.byte(c))
+    end))
+  end
+end
+
 return _ENV;

scripts/domino-enum-users.nse

@@ -103,7 +103,7 @@ action = function(host, port)
 		helper:disconnect()
 		
 		if ( status and data and path ) then
-			local filename = ("%s/%s.id"):format(path, username )
+			local filename = path .. "/" .. stdnse.filename_escape(u_details.fullname .. ".id")
 			local status, err = saveIDFile( filename, data )
 			
 			if ( status ) then

scripts/hostmap-bfk.nse

@@ -68,7 +68,7 @@ categories = {"external", "discovery", "intrusive"}
 
 local HOSTMAP_SERVER = "www.bfk.de"
 
-local filename_escape, write_file
+local write_file
 
 hostrule = function(host)
   return not ipOps.isPrivate(host.ip)
@@ -106,7 +106,7 @@ action = function(host)
 
   local filename_prefix = stdnse.get_script_args("hostmap-bfk.prefix")
   if filename_prefix then
-    local filename = filename_prefix .. filename_escape(host.targetname or host.ip)
+    local filename = filename_prefix .. stdnse.filename_escape(host.targetname or host.ip)
     local status, err = write_file(filename, hostnames_str .. "\n")
     if status then
       output_tab.filename = filename
@@ -118,13 +118,6 @@ action = function(host)
   return output_tab
 end
 
--- Escape some potentially unsafe characters in a string meant to be a filename.
-function filename_escape(s)
-  return string.gsub(s, "[\0/=]", function(c)
-    return string.format("=%02X", string.byte(c))
-  end)
-end
-
 function write_file(filename, contents)
   local f, err = io.open(filename, "w")
   if not f then

scripts/hostmap-ip2hosts.nse

@@ -53,7 +53,7 @@ local target = require "target"
 local HOSTMAP_BING_SERVER = "www.ip2hosts.com"
 local HOSTMAP_DEFAULT_PROVIDER = "ALL"
 
-local filename_escape, write_file
+local write_file
 
 hostrule = function(host)
   return not ipOps.isPrivate(host.ip)
@@ -99,7 +99,7 @@ action = function(host)
   output_tab.hosts = hostnames
   --write to file
   if filename_prefix then
-    local filename = filename_prefix .. filename_escape(host.targetname or host.ip)
+    local filename = filename_prefix .. stdnse.filename_escape(host.targetname or host.ip)
     hostnames_str = stdnse.strjoin("\n", hostnames)
     local status, err = write_file(filename, hostnames_str)
     if status then
@@ -112,13 +112,6 @@ action = function(host)
   return output_tab
 end
 
--- Escape some potentially unsafe characters in a string meant to be a filename.
-function filename_escape(s)
-  return string.gsub(s, "[%z/=]", function(c)
-    return string.format("=%02X", string.byte(c))
-  end)
-end
-
 function write_file(filename, contents)
   local f, err = io.open(filename, "w")
   if not f then

scripts/http-config-backup.nse

@@ -209,7 +209,7 @@ action = function (host, port)
       if (response.status == 200) then
         -- check it if is valid before inserting
         if cfg.check(response.body) then
-          local filename = ((host.targetname or host.ip) .. url_path):gsub("/", "-");
+          local filename = stdnse.escape_filename((host.targetname or host.ip) .. url_path)
 
           -- save the content
           if save then

scripts/http-domino-enum-passwords.nse

@@ -315,9 +315,10 @@ action = function(host, port)
 				http_response = http.get( vhost or host, port, u_details.idfile, { auth = { username = user, password = pass }, no_cache = true })	
 
 				if ( http_response.status == 200 ) then
-					local status, err = saveIDFile( ("%s/%s.id"):format(download_path, u_details.fullname), http_response.body )
+					local filename = download_path .. "/" .. stdnse.filename_escape(u_details.fullname .. ".id")
+					local status, err = saveIDFile( filename, http_response.body )
 					if ( status ) then
-						table.insert( id_files, ("%s ID File has been downloaded (%s/%s.id)"):format(u_details.fullname, download_path, u_details.fullname) )
+						table.insert( id_files, ("%s ID File has been downloaded (%s)"):format(u_details.fullname, filename) )
 					else
 						table.insert( id_files, ("%s ID File was not saved (error: %s)"):format(u_details.fullname, err ) )
 					end

scripts/ms-sql-dump-hashes.nse

@@ -119,7 +119,7 @@ action = function( host, port )
 				local filename
 				if ( dir ) then
 					local instance = instance:GetName():match("%\\+(.+)$") or instance:GetName()
-					filename = ("%s/%s_%s_ms-sql_hashes.txt"):format(dir, host.ip, instance)
+					filename = dir .. "/" .. stdnse.filename_escape(("%s_%s_ms-sql_hashes.txt"):format(host.ip, instance))
 					saveToFile(filename, instanceOutput[1])
 				end				
 			end

scripts/snmp-ios-config.nse

@@ -184,7 +184,7 @@ action = function(host, port)
 			result = ( infile and infile:getContent() )
 			
 			if ( tftproot ) then
-				local fname = tftproot .. host.ip .. "-config"
+				local fname = tftproot .. stdnse.filename_escape(host.ip .. "-config")
 				local file, err = io.open(fname, "w")
 				if ( file ) then
 					file:write(result)

scripts/stuxnet-detect.nse

@@ -81,7 +81,7 @@ local function check_infected(host, path, save)
 
 		fmt = save:gsub("%%h", host.ip)
 		fmt = fmt:gsub("%%v", version)
-		file = io.open(fmt, "w")
+		file = io.open(stdnse.filename_escape(fmt), "w")
 		if file then
 			stdnse.print_debug(1, "Wrote %d bytes to file %s.", #result.arguments, fmt)
 			file:write(result.arguments)