diff --git a/infer/src/quandary/ClangTaintAnalysis.ml b/infer/src/quandary/ClangTaintAnalysis.ml
index d1ddb9d1c..1921fadb5 100644
--- a/infer/src/quandary/ClangTaintAnalysis.ml
+++ b/infer/src/quandary/ClangTaintAnalysis.ml
@@ -23,24 +23,50 @@ include
       | QuandarySummary.AccessTree.Clang tree -> tree
       | _ -> assert false
 
-    let handle_unknown_call _ ret_typ_opt actuals _ =
-      match ret_typ_opt, List.rev actuals with
-      | Some _, _ ->
-          (* propagate taint from actuals to return value *)
-          [TaintSpec.Propagate_to_return]
-      | None, [] ->
-          []
-      | None,
-        HilExp.AccessPath ((Var.ProgramVar pvar, { desc=Typ.Tptr (_, Typ.Pk_pointer) }), []) :: _
-        when Pvar.is_frontend_tmp pvar ->
-          (* no return value, but the frontend has introduced a dummy return variable and will
-             assign the return value to this variable. So propagate taint to the dummy return
-             variable *)
-          let actual_index = List.length actuals - 1 in
-          [TaintSpec.Propagate_to_actual actual_index]
-      | None, _ ->
-          (* no return value; propagate taint from actuals to receiver *)
+    let handle_unknown_call pname ret_typ_opt actuals _ =
+      let handle_generic_unknown ret_typ_opt actuals =
+        match ret_typ_opt, List.rev actuals with
+        | Some _, _ ->
+            (* propagate taint from actuals to return value *)
+            [TaintSpec.Propagate_to_return]
+        | None, [] ->
+            []
+        | None, _ when Typ.Procname.is_constructor pname ->
+            (* "this" is always the first arg of a constructor; propagate taint there *)
+            [TaintSpec.Propagate_to_receiver]
+        | None,
+          HilExp.AccessPath ((Var.ProgramVar pvar, { desc=Typ.Tptr (_, Typ.Pk_pointer) }), []) :: _
+          when Pvar.is_frontend_tmp pvar ->
+            (* no return value, but the frontend has introduced a dummy return variable and will
+               assign the return value to this variable. So propagate taint to the dummy return
+               variable *)
+            let actual_index = List.length actuals - 1 in
+            [TaintSpec.Propagate_to_actual actual_index]
+        | None, _ ->
+            (* no return value; propagate taint from actuals to receiver *)
+            [TaintSpec.Propagate_to_receiver] in
+
+      (* if we have a specific model for a procedure, use that. otherwise, use the generic
+         heuristics for dealing with unknown code *)
+      match Typ.Procname.get_method pname with
+      | "operator+="
+      | "operator-="
+      | "operator*="
+      | "operator/="
+      | "operator%="
+      | "operator<<="
+      | "operator>>="
+      | "operator&="
+      | "operator^="
+      | "operator|=" ->
+          [TaintSpec.Propagate_to_receiver; TaintSpec.Propagate_to_return]
+      | "memcpy" | "memmove" | "strcpy" | "strncpy" ->
+          [TaintSpec.Propagate_to_receiver; TaintSpec.Propagate_to_return]
+      | "sprintf" ->
           [TaintSpec.Propagate_to_receiver]
+      | other ->
+          L.d_strln ("generic unknown " ^ other);
+          handle_generic_unknown ret_typ_opt actuals
 
     let is_taintable_type _ = true
   end)
diff --git a/infer/src/quandary/TaintAnalysis.ml b/infer/src/quandary/TaintAnalysis.ml
index e3d497004..ab742e802 100644
--- a/infer/src/quandary/TaintAnalysis.ml
+++ b/infer/src/quandary/TaintAnalysis.ml
@@ -414,15 +414,23 @@ module Make (TaintSpecification : TaintSpec.S) = struct
                   astate_with_sink in
 
             let astate_with_summary =
+              (* hack for default C++ constructors, which get translated as an empty body (and
+                 will thus have an empty summary). We don't want that because we want to be able to
+                 propagate taint from comstructor parameters to the constructed object. so we treat
+                 the empty constructor as a skip function instead *)
+              let is_dummy_cpp_constructor summary pname =
+                Typ.Procname.is_c_method pname &&
+                Typ.Procname.is_constructor pname &&
+                TaintDomain.BaseMap.is_empty (TaintSpecification.of_summary_access_tree summary) in
               if sinks <> [] || Option.is_some source
               then
                 (* don't use a summary for a procedure that is a direct source or sink *)
                 astate_with_source
               else
                 match Summary.read_summary proc_data.pdesc callee_pname with
-                | Some summary ->
+                | Some summary when not (is_dummy_cpp_constructor summary callee_pname) ->
                     apply_summary ret_opt actuals summary astate_with_source proc_data call_site
-                | None ->
+                | _ ->
                     handle_unknown_call callee_pname astate_with_source in
             Domain.join astate_acc astate_with_summary in
 
diff --git a/infer/tests/codetoanalyze/cpp/quandary/issues.exp b/infer/tests/codetoanalyze/cpp/quandary/issues.exp
index cb7854c99..0deab8bd6 100644
--- a/infer/tests/codetoanalyze/cpp/quandary/issues.exp
+++ b/infer/tests/codetoanalyze/cpp/quandary/issues.exp
@@ -42,6 +42,34 @@ codetoanalyze/cpp/quandary/pointers.cpp, pointers::assign_pointer_pass_to_sink_b
 codetoanalyze/cpp/quandary/pointers.cpp, pointers::assign_source_by_reference_bad1, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,return from pointers::assign_source_by_reference,call to __infer_taint_sink]
 codetoanalyze/cpp/quandary/pointers.cpp, pointers::assign_source_by_reference_bad2, 2, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,return from pointers::assign_source_by_reference,call to __infer_taint_sink]
 codetoanalyze/cpp/quandary/pointers.cpp, pointers::assign_source_by_reference_bad3, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,return from pointers::assign_source_by_reference,return from pointers::call_assign_source_by_reference,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::append_bad1, 2, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::append_bad2, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::assign_bad1, 2, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::assign_bad2, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::concat_bad1, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::concat_bad2, 4, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::concat_bad3, 2, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::constructor_bad1, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::constructor_bad2, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::constructor_bad3, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,flow through std::__wrap_iter<char*>_operator+,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::format_bad1, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,flow through strings::format1<std::basic_string<char>_&>,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::format_bad2, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,flow through strings::format2<std::basic_string<char>_&>,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::format_bad3, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::format_bad4, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::format_varargs_bad, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::insert_bad1, 2, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::insert_bad2, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::memchr_bad, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::memcpy_bad, 4, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::memmove_bad, 4, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::replace_bad1, 2, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::replace_bad2, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::sprintf_bad1, 4, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::sprintf_bad2, 4, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::strcpy_bad1, 4, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::strcpy_bad2, 4, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::strncpy_bad, 4, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
+codetoanalyze/cpp/quandary/strings.cpp, strings::swap_bad, 4, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
 codetoanalyze/cpp/quandary/unknown_code.cpp, unknown_code::direct_bad, 2, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
 codetoanalyze/cpp/quandary/unknown_code.cpp, unknown_code::skip_indirect_bad, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,flow through unknown_code::skip_indirect,call to __infer_taint_sink]
 codetoanalyze/cpp/quandary/unknown_code.cpp, unknown_code::skip_pointer_bad, 3, QUANDARY_TAINT_ERROR, [return from __infer_taint_source,call to __infer_taint_sink]
diff --git a/infer/tests/codetoanalyze/cpp/quandary/strings.cpp b/infer/tests/codetoanalyze/cpp/quandary/strings.cpp
new file mode 100644
index 000000000..0d871477e
--- /dev/null
+++ b/infer/tests/codetoanalyze/cpp/quandary/strings.cpp
@@ -0,0 +1,214 @@
+/*
+ * Copyright (c) 2016 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#include <stdio.h>
+#include <string>
+
+extern std::string __infer_taint_source();
+extern void __infer_taint_sink(std::string);
+
+// tests related to string manipulation, format strings, etc.
+namespace strings {
+
+void sprintf_bad1() {
+  char laundered_source[50];
+  auto source = __infer_taint_source().c_str();
+  sprintf(laundered_source, "%s", source);
+  __infer_taint_sink(laundered_source);
+}
+
+void sprintf_bad2() {
+  char laundered_source[50];
+  auto source = __infer_taint_source().c_str();
+  sprintf(laundered_source, "%s%s%d", "a", source, 1);
+  __infer_taint_sink(laundered_source);
+}
+
+void strcpy_bad1() {
+  char laundered_source[50];
+  auto source = __infer_taint_source().c_str();
+  auto copy = strcpy(laundered_source, source);
+  __infer_taint_sink(copy);
+}
+
+void strcpy_bad2() {
+  char laundered_source[50];
+  auto source = __infer_taint_source().c_str();
+  strcpy(laundered_source, source);
+  __infer_taint_sink(laundered_source);
+}
+
+void strncpy_bad() {
+  char laundered_source[50];
+  auto source = __infer_taint_source().c_str();
+  strncpy(laundered_source, source, 50);
+  __infer_taint_sink(laundered_source);
+}
+
+void memcpy_bad() {
+  char laundered_source[50];
+  auto source = __infer_taint_source().c_str();
+  memcpy(laundered_source, source, 50);
+  __infer_taint_sink(laundered_source);
+}
+
+void memmove_bad() {
+  char laundered_source[50];
+  auto source = __infer_taint_source().c_str();
+  auto copy = (char*)memmove(laundered_source, source, 50);
+  __infer_taint_sink(copy);
+}
+
+void memchr_bad() {
+  auto source = __infer_taint_source().c_str();
+  auto laundered_source = (char*)memchr(source, 'a', 10);
+  __infer_taint_sink(laundered_source);
+}
+
+void constructor_bad1() {
+  auto source = __infer_taint_source();
+  auto laundered_source = std::string(source);
+  __infer_taint_sink(laundered_source);
+}
+
+void constructor_bad2() {
+  auto source = __infer_taint_source();
+  auto laundered_source = std::string(source, 0, 5);
+  __infer_taint_sink(laundered_source);
+}
+
+void constructor_bad3() {
+  auto source = __infer_taint_source();
+  auto laundered_source = std::string(source.begin(), source.begin() + 5);
+  __infer_taint_sink(laundered_source);
+}
+
+void concat_bad1() {
+  auto source = __infer_taint_source();
+  source += "other string";
+  __infer_taint_sink(source);
+}
+
+void concat_bad2() {
+  auto source = __infer_taint_source();
+  auto laundered_source = std::string("string");
+  laundered_source += source;
+  __infer_taint_sink(laundered_source);
+}
+
+void concat_bad3() {
+  auto source = __infer_taint_source();
+  __infer_taint_sink(source += "string");
+}
+
+void append_bad1() {
+  auto source = __infer_taint_source();
+  __infer_taint_sink(std::string("string").append(source));
+}
+
+void append_bad2() {
+  auto source = __infer_taint_source();
+  source.append("string");
+  __infer_taint_sink(source);
+}
+
+void assign_bad1() {
+  auto source = __infer_taint_source();
+  __infer_taint_sink(std::string("string").assign(source));
+}
+
+void assign_bad2() {
+  auto source = __infer_taint_source();
+  source.assign("string");
+  __infer_taint_sink(source);
+}
+
+void insert_bad1() {
+  auto source = __infer_taint_source();
+  __infer_taint_sink(std::string("string").assign(source));
+}
+
+void insert_bad2() {
+  auto source = __infer_taint_source();
+  source.insert(0, "string");
+  __infer_taint_sink(source);
+}
+
+void replace_bad1() {
+  auto source = __infer_taint_source();
+  __infer_taint_sink(std::string("string").replace(0, 5, source));
+}
+
+void replace_bad2() {
+  auto source = __infer_taint_source();
+  source.replace(0, 5, "string");
+  __infer_taint_sink(source);
+}
+
+void swap_bad() {
+  auto source = __infer_taint_source();
+  auto laundered_source = std::string("string");
+  laundered_source.swap(source);
+  __infer_taint_sink(laundered_source);
+}
+
+template <class... Args>
+class Formatter {
+
+ public:
+  explicit Formatter(std::string str, Args&&... args);
+  std::string str();
+};
+
+template <class... Args>
+Formatter<Args...> format1(std::string fmt, Args&&... args) {
+  return Formatter<Args...>(fmt, std::forward<Args>(args)...);
+}
+
+template <class... Args>
+Formatter<Args...>* format2(std::string fmt, Args&&... args) {
+  return new Formatter<Args...>(fmt, std::forward<Args>(args)...);
+}
+
+template <class... Args>
+Formatter<Args...> format3(std::string fmt, Args&&... args);
+
+template <class... Args>
+Formatter<Args...>* format4(std::string fmt, Args&&... args);
+
+void format_bad1() {
+  auto source = __infer_taint_source();
+  auto laundered_source = format1("%s", source).str();
+  __infer_taint_sink(laundered_source);
+}
+
+void format_bad2() {
+  auto source = __infer_taint_source();
+  auto laundered_source = format2("%s", source)->str();
+  __infer_taint_sink(laundered_source);
+}
+
+void format_bad3() {
+  auto source = __infer_taint_source();
+  auto laundered_source = format3("%s", source).str();
+  __infer_taint_sink(laundered_source);
+}
+
+void format_bad4() {
+  auto source = __infer_taint_source();
+  auto laundered_source = format4("%s", source)->str();
+  __infer_taint_sink(laundered_source);
+}
+
+void format_varargs_bad() {
+  auto source = __infer_taint_source();
+  auto laundered_source = format3("%s%s", "a", source, "b").str();
+  __infer_taint_sink(laundered_source);
+}
+}