Merge pull request #1945 from AFLplusplus/stable

push back to dev

2 files changed, 97 insertions, 0 deletions

diff --git a/instrumentation/README.injections.md b/instrumentation/README.injections.md
new file mode 100644
index 00000000..16cc3713
--- /dev/null
+++ b/instrumentation/README.injections.md
@@ -0,0 +1,48 @@
+# Injection fuzzing
+
+Coverage guided fuzzing so far is only able to detect crashes, so usually
+memory corruption issues, or - if implemented by hand in the harness -
+invariants.
+
+This is a proof-of-concept implementation to additionally hunt for injection
+vulnerabilities.
+It works by instrumenting calls to specific functions and parsing the
+query parameter for a specific unescaped dictionary string, and if detected,
+crashes the target.
+
+This has a very low false positive rate.
+But obviously this can only find injection vulnerailities that are suspectible
+to this specific (but most common) issue. Hence in a rare kind of injection
+vulnerability this won't find the bug - and be a false negative.
+But this can be tweaked by the user - see the HOW TO MODIFY section below.
+
+## How to use
+
+Set one or more of the following environment variables for **compiling**
+the target and - *this is important* - when **fuzzing** the target:
+
+ - `AFL_LLVM_INJECTIONS_SQL`
+ - `AFL_LLVM_INJECTIONS_LDAP`
+ - `AFL_LLVM_INJECTIONS_XSS`
+
+Alternatively you can set `AFL_LLVM_INJECTIONS_ALL` to enable all.
+
+## How to modify
+
+If you want to add more fuctions to check for e.g. SQL injections:
+Add these to `instrumentation/injection-pass.cc` and recompile.
+
+If you want to test for more injection inputs:
+Add the dictionary tokens to `src/afl-fuzz.c` and the check for them to
+`instrumentation/afl-compiler-rt.o.c`.
+
+If you want to add new injection targets:
+You will have to edit all three files.
+
+Just search for:
+```
+// Marker: ADD_TO_INJECTIONS
+```
+in the files to see where this needs to be added.
+
+**NOTE:** pull requests to improve this feature are highly welcome :-)
diff --git a/instrumentation/afl-compiler-rt.o.c b/instrumentation/afl-compiler-rt.o.c
index def59b6b..39a762b6 100644
--- a/instrumentation/afl-compiler-rt.o.c
+++ b/instrumentation/afl-compiler-rt.o.c
@@ -92,6 +92,8 @@ extern ssize_t _kern_write(int fd, off_t pos, const void *buffer,
                            size_t bufferSize);
 #endif  // HAIKU
 
+char *strcasestr(const char *haystack, const char *needle);
+
 static u8  __afl_area_initial[MAP_INITIAL_SIZE];
 static u8 *__afl_area_ptr_dummy = __afl_area_initial;
 static u8 *__afl_area_ptr_backup = __afl_area_initial;
@@ -2670,5 +2672,52 @@ void __afl_set_persistent_mode(u8 mode) {
 
 }
 
+// Marker: ADD_TO_INJECTIONS
+
+void __afl_injection_sql(u8 *buf) {
+
+  if (likely(buf)) {
+
+    if (unlikely(strstr((char *)buf, "'\"\"'"))) {
+
+      fprintf(stderr, "ALERT: Detected SQL injection in query: %s\n", buf);
+      abort();
+
+    }
+
+  }
+
+}
+
+void __afl_injection_ldap(u8 *buf) {
+
+  if (likely(buf)) {
+
+    if (unlikely(strstr((char *)buf, "*)(1=*))(|"))) {
+
+      fprintf(stderr, "ALERT: Detected LDAP injection in query: %s\n", buf);
+      abort();
+
+    }
+
+  }
+
+}
+
+void __afl_injection_xss(u8 *buf) {
+
+  if (likely(buf)) {
+
+    if (unlikely(strstr((char *)buf, "1\"><\""))) {
+
+      fprintf(stderr, "ALERT: Detected XSS injection in content: %s\n", buf);
+      abort();
+
+    }
+
+  }
+
+}
+
 #undef write_error