diff --git a/src/ICMP.cc b/src/ICMP.cc
index 05a6b67dff..b06c6440e1 100644
--- a/src/ICMP.cc
+++ b/src/ICMP.cc
@@ -49,9 +49,7 @@ void ICMP_Analyzer::DeliverPacket(int len, const u_char* data,
 
 	const struct icmp* icmpp = (const struct icmp*) data;
 
-	assert(caplen >= len); // Should have been caught earlier already.
-
-	if ( ! ignore_checksums )
+	if ( ! ignore_checksums && caplen >= len )
 		{
 		int chksum = 0;
 
diff --git a/testing/btest/Baseline/core.truncation/output b/testing/btest/Baseline/core.truncation/output
index f3d64b8b28..95d9073648 100644
--- a/testing/btest/Baseline/core.truncation/output
+++ b/testing/btest/Baseline/core.truncation/output
@@ -22,3 +22,11 @@
 #fields	ts	uid	id.orig_h	id.orig_p	id.resp_h	id.resp_p	name	addl	notice	peer
 #types	time	string	addr	port	addr	port	string	string	bool	string
 1334094648.590126	-	-	-	-	-	truncated_IP	-	F	bro
+#separator \x09
+#set_separator	,
+#empty_field	(empty)
+#unset_field	-
+#path	weird
+#fields	ts	uid	id.orig_h	id.orig_p	id.resp_h	id.resp_p	name	addl	notice	peer
+#types	time	string	addr	port	addr	port	string	string	bool	string
+1338328954.078361	-	-	-	-	-	internally_truncated_header	-	F	bro
diff --git a/testing/btest/Traces/trunc/icmp-header-trunc.pcap b/testing/btest/Traces/trunc/icmp-header-trunc.pcap
new file mode 100644
index 0000000000..5765cf2886
Binary files /dev/null and b/testing/btest/Traces/trunc/icmp-header-trunc.pcap differ
diff --git a/testing/btest/Traces/trunc/icmp-payload-trunc.pcap b/testing/btest/Traces/trunc/icmp-payload-trunc.pcap
new file mode 100644
index 0000000000..13607dd50c
Binary files /dev/null and b/testing/btest/Traces/trunc/icmp-payload-trunc.pcap differ
diff --git a/testing/btest/core/truncation.test b/testing/btest/core/truncation.test
index ee8bdd5bf9..3406879183 100644
--- a/testing/btest/core/truncation.test
+++ b/testing/btest/core/truncation.test
@@ -6,4 +6,17 @@
 # @TEST-EXEC: cat weird.log >> output
 # @TEST-EXEC: bro -r $TRACES/trunc/ip6-ext-trunc.pcap
 # @TEST-EXEC: cat weird.log >> output
+
+# If an ICMP packet's payload is truncated due to too small snaplen,
+# the checksum calculation is bypassed (and Bro doesn't crash, of course).
+
+# @TEST-EXEC: rm -f weird.log
+# @TEST-EXEC: bro -r $TRACES/trunc/icmp-payload-trunc.pcap
+# @TEST-EXEC: test ! -e weird.log
+
+# If an ICMP packet has the ICMP header truncated due to too small snaplen,
+# an internally_truncated_header weird gets generated.
+
+# @TEST-EXEC: bro -r $TRACES/trunc/icmp-header-trunc.pcap
+# @TEST-EXEC: cat weird.log >> output
 # @TEST-EXEC: btest-diff output