diff --git a/lib/vauth/.checksrc b/lib/vauth/.checksrc
index 9066946c89..eff4bc0a3f 100644
--- a/lib/vauth/.checksrc
+++ b/lib/vauth/.checksrc
@@ -1,2 +1,3 @@
-enable STRERROR
-enable STRNCPY
+banfunc strerror
+banfunc strncpy
+banfunc sscanf
diff --git a/lib/vquic/.checksrc b/lib/vquic/.checksrc
index 9066946c89..eff4bc0a3f 100644
--- a/lib/vquic/.checksrc
+++ b/lib/vquic/.checksrc
@@ -1,2 +1,3 @@
-enable STRERROR
-enable STRNCPY
+banfunc strerror
+banfunc strncpy
+banfunc sscanf
diff --git a/lib/vssh/.checksrc b/lib/vssh/.checksrc
index 9066946c89..eff4bc0a3f 100644
--- a/lib/vssh/.checksrc
+++ b/lib/vssh/.checksrc
@@ -1,2 +1,3 @@
-enable STRERROR
-enable STRNCPY
+banfunc strerror
+banfunc strncpy
+banfunc sscanf
diff --git a/lib/vtls/.checksrc b/lib/vtls/.checksrc
index 9066946c89..eff4bc0a3f 100644
--- a/lib/vtls/.checksrc
+++ b/lib/vtls/.checksrc
@@ -1,2 +1,3 @@
-enable STRERROR
-enable STRNCPY
+banfunc strerror
+banfunc strncpy
+banfunc sscanf
diff --git a/tests/server/.checksrc b/tests/server/.checksrc
index ac086ea4c6..fef8744a51 100644
--- a/tests/server/.checksrc
+++ b/tests/server/.checksrc
@@ -1 +1 @@
-banfunc STRNCPY
+banfunc strncpy