Wireshark is a trusted tool for network analysis, but sometimes, even the best software has vulnerabilities. One such example is CVE-2023-4513, a memory leak in the Bluetooth Service Discovery Protocol (SDP) dissector that affects certain versions of Wireshark. This seemingly small issue can turn into a serious Denial of Service (DoS) condition with surprisingly little effort.
What is CVE-2023-4513?
CVE-2023-4513 is a memory leak bug in Wireshark's Bluetooth SDP dissector. This part of Wireshark is used to interpret Bluetooth SDP packets. If it's fed a maliciously crafted packet or capture file, it can start leaking memory every time it tries to decode those packets. If enough bad packets are injected, this leak can consume a substantial amount of RAM, causing Wireshark — or even the entire system — to slow down or crash. That's why this is classified as a Denial of Service (DoS) issue.
Why should you care?
Even if you don't work directly with Bluetooth, remember that anyone can send you a malicious .pcap file and ask you to "take a quick look." That file could bring your system to its knees.
Provide a malicious capture file containing such packets.
If Wireshark is running the affected version and you open the bad capture (or capture live), the SDP dissector tries to parse the malformed packets. Each parsed packet causes a little bit of memory not to be freed (a leak). With enough such packets, memory usage can blow up very quickly.
Proof-of-Concept Code
Let’s create a simple scenario where you simulate the issue with a fake .pcapng file containing bad SDP data.
> NOTE: For safety, do not open such files in a production system or on unpatched Wireshark!
Here’s a minimal Python script using scapy that crafts a BLE SDP packet and adds it to a pcap file:
from scapy.all import *
# Define a malformed Bluetooth SDP PDU
# (The real exploit would carefully craft this to trigger the leak)
bad_sdp_payload = b"\x02\x00\x00" + (b"\xff" * 100)
# Create a dummy L2CAP layer (real attack would use proper Bluetooth headers)
pkt = Raw(load=bad_sdp_payload)
# Write multiple packets to a pcap to exaggerate the leak
packets = [pkt for _ in range(500)]
# Save the malicious pcap
wrpcap("malicious_sdp_leak.pcap", packets)
print("Generated malicious SDP pcap file as 'malicious_sdp_leak.pcap'")
The Exploit in Action (Screenshot)
While we can't post images here, you can try it yourself — open the generated file in Wireshark and monitor memory with a tool like Task Manager (Windows) or top/htop (Linux). You’ll see the RAM steadily go up as Wireshark processes the file.
How to Fix
Upgrade Wireshark.
3.6.16 and later
Or, if you absolutely cannot upgrade, you can disable the Bluetooth SDP dissector in Analyze > Enabled Protocols... (search for "btsdp" and uncheck it).
References and Further Reading
- Wireshark Security Advisory: wnpa-sec-2023-16
- NIST NVD Entry for CVE-2023-4513
- Wireshark Release Notes
- Wireshark's Official Download Page
Final Thoughts
CVE-2023-4513 is a classic example of how even non-"remote code execution" bugs can cause big trouble. Memory leaks are slow killers, but they can achieve DoS just as effectively. If you use Wireshark, keep it up to date, and be especially wary of opening captures from untrusted sources.
Timeline
Published on: 08/24/2023 07:15:00 UTC
Last modified on: 09/15/2023 22:15:00 UTC