diff --git a/lib/msf/core/exploit/remote/smtp_deliver.rb b/lib/msf/core/exploit/remote/smtp_deliver.rb
index c0a136e3ee..d44609f8ce 100755
--- a/lib/msf/core/exploit/remote/smtp_deliver.rb
+++ b/lib/msf/core/exploit/remote/smtp_deliver.rb
@@ -80,7 +80,7 @@ module Exploit::Remote::SMTPDeliver
 
     if res =~ /STARTTLS/
       print_status("Starting tls")
-      raw_send_recv("STARTTLS\r\n", nsock)
+      smtp_send_recv("STARTTLS\r\n", nsock)
 
       [:high, :medium, :default].each do |level|
         begin
@@ -91,12 +91,12 @@ module Exploit::Remote::SMTPDeliver
           print_status 'Could not negotiate SSL, falling back to older ciphers'
           nsock.close
           nsock, res = connect_ehlo(global)
-          raw_send_recv("STARTTLS\r\n", nsock)
+          smtp_send_recv("STARTTLS\r\n", nsock)
           raise if level == :default
         end
       end
 
-      res = raw_send_recv("EHLO #{domain}\r\n", nsock)
+      res = smtp_send_recv("EHLO #{domain}\r\n", nsock)
     end
 
     unless datastore['PASSWORD'].empty? and datastore["USERNAME"].empty?
@@ -106,7 +106,7 @@ module Exploit::Remote::SMTPDeliver
           # Have to double the username.  SMTP auth is weird
           user = "#{datastore["USERNAME"]}\0" * 2
           auth = Rex::Text.encode_base64("#{user}#{datastore["PASSWORD"]}")
-          res = raw_send_recv("AUTH PLAIN #{auth}\r\n", nsock)
+          res = smtp_send_recv("AUTH PLAIN #{auth}\r\n", nsock)
           unless res[0..2] == '235'
             print_error("Authentication failed, quitting")
             disconnect(nsock)
@@ -119,9 +119,9 @@ module Exploit::Remote::SMTPDeliver
         if datastore["USERNAME"] and not datastore["USERNAME"].empty?
           user = Rex::Text.encode_base64("#{datastore["USERNAME"]}")
           auth = Rex::Text.encode_base64("#{datastore["PASSWORD"]}")
-          raw_send_recv("AUTH LOGIN\r\n",nsock)
-          raw_send_recv("#{user}\r\n",nsock)
-          res = raw_send_recv("#{auth}\r\n",nsock)
+          smtp_send_recv("AUTH LOGIN\r\n", nsock)
+          smtp_send_recv("#{user}\r\n", nsock)
+          res = smtp_send_recv("#{auth}\r\n", nsock)
           unless res[0..2] == '235'
             print_error("Authentication failed, quitting")
             disconnect(nsock)
@@ -147,7 +147,7 @@ module Exploit::Remote::SMTPDeliver
     vprint_status("Connecting to SMTP server #{rhost}:#{rport}...")
     nsock = connect(global)
 
-    [nsock, raw_send_recv("EHLO #{domain}\r\n", nsock)]
+    [nsock, smtp_send_recv("EHLO #{domain}\r\n", nsock)]
   end
 
   def bad_address(address)
@@ -181,10 +181,10 @@ module Exploit::Remote::SMTPDeliver
       nsock = connect_login(false)
     end
 
-    raw_send_recv("MAIL FROM: <#{mailfrom}>\r\n", nsock)
-    res = raw_send_recv("RCPT TO: <#{mailto}>\r\n", nsock)
+    smtp_send_recv("MAIL FROM: <#{mailfrom}>\r\n", nsock)
+    res = smtp_send_recv("RCPT TO: <#{mailto}>\r\n", nsock)
     if res && res[0..2] == '250'
-      resp = raw_send_recv("DATA\r\n", nsock)
+      resp = smtp_send_recv("DATA\r\n", nsock)
 
       # If the user supplied a Date field, use that, else use the current
       # DateTime in the proper RFC2822 format.
@@ -211,7 +211,7 @@ module Exploit::Remote::SMTPDeliver
         full_msg << data
         # Escape leading dots in the mail messages so there are no false EOF
         full_msg.gsub!(/(?m)^\./, '..')
-        send_status = raw_send_recv("#{full_msg}\r\n.\r\n", nsock)
+        send_status = smtp_send_recv("#{full_msg}\r\n.\r\n", nsock)
       end
     else
       print_error "Server refused to send to <#{mailto}>"
@@ -226,12 +226,14 @@ module Exploit::Remote::SMTPDeliver
   end
 
   def disconnect(nsock=self.sock)
-    raw_send_recv("QUIT\r\n", nsock)
+    smtp_send_recv("QUIT\r\n", nsock)
     super
     @connected = false
   end
 
-  def raw_send_recv(cmd, nsock=self.sock)
+  # Send and receive a single command using SMTP protocol
+  # allowing for response continuation
+  def smtp_send_recv(cmd, nsock=self.sock)
     return false if not nsock
     if cmd =~ /AUTH PLAIN/
       # Don't print the user's plaintext password
@@ -244,7 +246,11 @@ module Exploit::Remote::SMTPDeliver
     begin
       nsock.put(cmd)
       res = nsock.get_once
-    rescue
+      while !(res =~ /(^|\r\n)\d{3}( .*|)\r\n$/) && chunk = nsock.get_once
+        res += chunk
+      end
+      raise RuntimeError.new("SMTP response is incomplete or contains extra data") unless res =~ /(^|\r\n)\d{3}( .*|)\r\n$/
+    rescue EOFError
       return nil
     end
     # Don't truncate the server output because it might be helpful for
diff --git a/modules/auxiliary/dos/smtp/sendmail_prescan.rb b/modules/auxiliary/dos/smtp/sendmail_prescan.rb
index fef094fe27..1496c2d575 100644
--- a/modules/auxiliary/dos/smtp/sendmail_prescan.rb
+++ b/modules/auxiliary/dos/smtp/sendmail_prescan.rb
@@ -38,10 +38,10 @@ class MetasploitModule < Msf::Auxiliary
 
       sploit = ("A" * 255 + ";") * 4 + "A" * 217 + ";" + "\x5c\xff" * 28
 
-      raw_send_recv("EHLO X\r\n")
-      raw_send_recv("MAIL FROM: #{datastore['MAILFROM']}\r\n")
+      smtp_send_recv("EHLO X\r\n")
+      smtp_send_recv("MAIL FROM: #{datastore['MAILFROM']}\r\n")
       print_status("Sending DoS packet.")
-      raw_send_recv("RCPT TO: #{sploit}\r\n")
+      smtp_send_recv("RCPT TO: #{sploit}\r\n")
 
       disconnect
     rescue ::Rex::ConnectionRefused, ::Rex::HostUnreachable, ::Rex::ConnectionTimeout
diff --git a/modules/auxiliary/scanner/smtp/smtp_relay.rb b/modules/auxiliary/scanner/smtp/smtp_relay.rb
index 287316508f..8db19c6fb5 100644
--- a/modules/auxiliary/scanner/smtp/smtp_relay.rb
+++ b/modules/auxiliary/scanner/smtp/smtp_relay.rb
@@ -82,19 +82,19 @@ class MetasploitModule < Msf::Auxiliary
     begin
       connect
 
-      res = raw_send_recv("EHLO X\r\n")
+      res = smtp_send_recv("EHLO X\r\n")
       vprint_status("#{res.inspect}")
 
-      res = raw_send_recv("#{mailfrom}\r\n")
+      res = smtp_send_recv("#{mailfrom}\r\n")
       vprint_status("#{res.inspect}")
 
-      res = raw_send_recv("#{mailto}\r\n")
+      res = smtp_send_recv("#{mailto}\r\n")
       vprint_status("#{res.inspect}")
 
-      res = raw_send_recv("DATA\r\n")
+      res = smtp_send_recv("DATA\r\n")
       vprint_status("#{res.inspect}")
 
-      res = raw_send_recv("#{Rex::Text.rand_text_alpha(rand(10)+5)}\r\n.\r\n")
+      res = smtp_send_recv("#{Rex::Text.rand_text_alpha(rand(10)+5)}\r\n.\r\n")
       vprint_status("#{res.inspect}")
 
       if res =~ /250/
diff --git a/modules/exploits/linux/smtp/exim4_dovecot_exec.rb b/modules/exploits/linux/smtp/exim4_dovecot_exec.rb
index caa972d00e..832904dd77 100644
--- a/modules/exploits/linux/smtp/exim4_dovecot_exec.rb
+++ b/modules/exploits/linux/smtp/exim4_dovecot_exec.rb
@@ -149,7 +149,7 @@ class MetasploitModule < Msf::Exploit::Remote
     end
 
     ehlo = datastore['EHLO']
-    ehlo_resp = raw_send_recv("EHLO #{ehlo}\r\n")
+    ehlo_resp = smtp_send_recv("EHLO #{ehlo}\r\n")
     ehlo_resp.each_line do |line|
       print_status("#{rhost}:#{rport} - EHLO: #{line.strip}")
     end
@@ -165,7 +165,7 @@ class MetasploitModule < Msf::Exploit::Remote
     from << "@#{ehlo}"
     to   = datastore['MAILTO']
 
-    resp = raw_send_recv("MAIL FROM: #{from}\r\n")
+    resp = smtp_send_recv("MAIL FROM: #{from}\r\n")
     resp ||= 'no response'
     msg = "MAIL: #{resp.strip}"
     if not resp or resp[0,3] != '250'
@@ -174,7 +174,7 @@ class MetasploitModule < Msf::Exploit::Remote
       print_status("#{rhost}:#{rport} - #{msg}")
     end
 
-    resp = raw_send_recv("RCPT TO: #{to}\r\n")
+    resp = smtp_send_recv("RCPT TO: #{to}\r\n")
     resp ||= 'no response'
     msg = "RCPT: #{resp.strip}"
     if not resp or resp[0,3] != '250'
@@ -183,7 +183,7 @@ class MetasploitModule < Msf::Exploit::Remote
       print_status("#{rhost}:#{rport} - #{msg}")
     end
 
-    resp = raw_send_recv("DATA\r\n")
+    resp = smtp_send_recv("DATA\r\n")
     resp ||= 'no response'
     msg = "DATA: #{resp.strip}"
     if not resp or resp[0,3] != '354'
@@ -196,7 +196,7 @@ class MetasploitModule < Msf::Exploit::Remote
     message <<  "\r\n"
     message << ".\r\n"
 
-    resp = raw_send_recv(message)
+    resp = smtp_send_recv(message)
     msg = "DELIVER: #{resp.strip}"
     if not resp or resp[0,3] != '250'
       fail_with(Failure::Unknown, "#{rhost}:#{rport} - #{msg}")
diff --git a/modules/exploits/unix/smtp/exim4_string_format.rb b/modules/exploits/unix/smtp/exim4_string_format.rb
index 89081ecff9..8caf16f6c0 100644
--- a/modules/exploits/unix/smtp/exim4_string_format.rb
+++ b/modules/exploits/unix/smtp/exim4_string_format.rb
@@ -113,7 +113,7 @@ class MetasploitModule < Msf::Exploit::Remote
       fail_with(Failure::Unknown, "Warning: This version of Exim is not exploitable")
     end
 
-    ehlo_resp = raw_send_recv("EHLO #{ehlo}\r\n")
+    ehlo_resp = smtp_send_recv("EHLO #{ehlo}\r\n")
     ehlo_resp.each_line do |line|
       print_status("EHLO: #{line.strip}")
     end
@@ -145,7 +145,7 @@ class MetasploitModule < Msf::Exploit::Remote
     from = datastore['MAILFROM']
     to   = datastore['MAILTO']
 
-    resp = raw_send_recv("MAIL FROM: #{from}\r\n")
+    resp = smtp_send_recv("MAIL FROM: #{from}\r\n")
     resp ||= 'no response'
     msg = "MAIL: #{resp.strip}"
     if not resp or resp[0,3] != '250'
@@ -154,7 +154,7 @@ class MetasploitModule < Msf::Exploit::Remote
       print_status(msg)
     end
 
-    resp = raw_send_recv("RCPT TO: #{to}\r\n")
+    resp = smtp_send_recv("RCPT TO: #{to}\r\n")
     resp ||= 'no response'
     msg = "RCPT: #{resp.strip}"
     if not resp or resp[0,3] != '250'
@@ -163,7 +163,7 @@ class MetasploitModule < Msf::Exploit::Remote
       print_status(msg)
     end
 
-    resp = raw_send_recv("DATA\r\n")
+    resp = smtp_send_recv("DATA\r\n")
     resp ||= 'no response'
     msg = "DATA: #{resp.strip}"
     if not resp or resp[0,3] != '354'
@@ -251,21 +251,21 @@ class MetasploitModule < Msf::Exploit::Remote
     sock.put body
 
     print_status("Ending first message.")
-    buf = raw_send_recv("\r\n.\r\n")
+    buf = smtp_send_recv("\r\n.\r\n")
     # Should be: "552 Message size exceeds maximum permitted\r\n"
     print_status("Result: #{buf.inspect}") if buf
 
     second_result = ""
 
     print_status("Sending second message ...")
-    buf = raw_send_recv("MAIL FROM: #{datastore['MAILFROM']}\r\n")
+    buf = smtp_send_recv("MAIL FROM: #{datastore['MAILFROM']}\r\n")
     # Should be: "sh-x.x$ " !!
     if buf
       print_status("MAIL result: #{buf.inspect}")
       second_result << buf
     end
 
-    buf = raw_send_recv("RCPT TO: #{datastore['MAILTO']}\r\n")
+    buf = smtp_send_recv("RCPT TO: #{datastore['MAILTO']}\r\n")
     # Should be: "sh: RCPT: command not found\n"
     if buf
       print_status("RCPT result: #{buf.inspect}")
@@ -296,7 +296,7 @@ class MetasploitModule < Msf::Exploit::Remote
 
     if resp !~ /Summary of my perl/
       print_status("Should have a shell now, sending payload...")
-      buf = raw_send_recv("\n" + payload.encoded + "\n\n")
+      buf = smtp_send_recv("\n" + payload.encoded + "\n\n")
       if buf
         if buf =~ /554 SMTP synchronization error/
           print_error("This target may be patched: #{buf.strip}")
diff --git a/spec/lib/msf/core/exploit/remote/smtp_delivery_spec.rb b/spec/lib/msf/core/exploit/remote/smtp_delivery_spec.rb
new file mode 100644
index 0000000000..60f1b5166e
--- /dev/null
+++ b/spec/lib/msf/core/exploit/remote/smtp_delivery_spec.rb
@@ -0,0 +1,93 @@
+RSpec.describe Msf::Exploit::Remote::SMTPDeliver do
+
+  context "#smtp_send_recv" do
+    subject(:instance) {
+      mod = Msf::Exploit::Remote.allocate
+      mod.extend described_class
+      mod
+    }
+
+
+    let (:socket) {
+      double(Rex::Socket::Tcp)
+    }
+    let (:cmd) {
+      "EHLO"
+    }
+    let(:ehlo_resp1) {
+      "250-ip-10-140-50-23.us-west-1.compute.internal\r\n250-XXXA\r250-PIPELINING\r\n250-AUTH CRAM-MD5 LOGIN PLAIN\r\n"
+    }
+    let(:ehlo_resp2) {
+      "250-SIZE 512000\r\n250-VRFY\r\n250-ETRN\r\n250-ENHANCEDSTATUSCODES\r\n250-8BITMIME\r\n250-XXXXXXXB\r\n250-XXXC\r\n"
+    }
+    let(:ehlo_resp3) {
+      "250 DSN"
+    }
+    let(:ehlo_resp4) {
+      "\r\n"
+    }
+
+    before {
+      allow(instance).to receive(:vprint_status)
+      allow(socket).to receive(:put)
+      allow(socket).to receive(:get_once).and_return(ehlo_resp1, ehlo_resp2, ehlo_resp3, ehlo_resp4)
+    }
+
+    it "should read the socket for continuation messages" do
+      response = instance.smtp_send_recv(cmd, socket)
+      expect(response).to end_with(ehlo_resp3 + ehlo_resp4)
+    end
+
+    context "when a single response occurs" do
+      let(:ehlo_resp1) {
+        "250 DSN\r\n"
+      }
+
+      before {
+        allow(socket).to receive(:get_once).and_return(ehlo_resp1)
+      }
+
+
+      it "passes" do
+        response = instance.smtp_send_recv(cmd, socket)
+        expect(response).to end_with(ehlo_resp1)
+      end
+    end
+
+    context "when the server response is terse" do
+      let(:ehlo_resp3) {
+        "250"
+      }
+
+      it "should support a final line with no space or extra data" do
+        response = instance.smtp_send_recv(cmd, socket)
+        expect(response).to end_with(ehlo_resp3 + ehlo_resp4)
+      end
+    end
+
+    context "when incomplete response is received" do
+      # a nil from `get_once` simulates a Timeout expired
+      let(:ehlo_resp4){
+        nil
+      }
+
+      it "should raise error when the response is incomplete" do
+        expect {instance.smtp_send_recv(cmd, socket)}.to raise_error RuntimeError
+      end
+    end
+
+    context "when excess data response is received" do
+      # a nil from `get_once` simulates a Timeout expired
+      let(:ehlo_resp3){
+        "250 DSN\r\n253 additional unexpected data"
+      }
+      let(:ehlo_resp4){
+        nil
+      }
+
+      it "should raise error when the response is incomplete" do
+        expect {instance.smtp_send_recv(cmd, socket)}.to raise_error RuntimeError
+      end
+    end
+  end
+end