NETRESEC Network Security Blog - Tag : decapsulation

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CapLoader 2.1.0 Released

CapLoader 2.1.0

CapLoader has been updated to version 2.1.0. The new release comes with better JA3/JA4 extraction and integration of additional threat-intel and OSINT services. We have also added support for more encapsulation protocols.

TLS Client Hello Reassembly

TLS handshakes no longer reliably fit in a single packet. Modern TLS features, like post-quantum key exchanges and Encrypted Client Hello (ECH), often expand handshake sizes across multiple TCP segments. The same trend appears in QUIC traffic, where TLS handshakes now often are too large to fit in a single UDP packet.

As a result, packet‑analysis tools that parse live traffic or PCAP files (like CapLoader) must cache partial TLS handshakes and reassemble them to recover the complete TLS ClientHello messages. NetworkMiner and FlowCarp already perform TLS handshake reassembly; CapLoader now supports it as well. This enables CapLoader to extract metadata from large TLS handshakes, including SNI hostnames, JA3 hashes and JA4 fingerprints.

TLS and QUIC sessions in CapLoader 2.1.0.0

The screenshot above shows CapLoader displaying information extracted from PCAP files that contain TLS and QUIC traffic with multi‑segment TLS 1.3 handshakes. The visible JA4 fingerprints for the client handshakes are:

  • q13d0311h3_55b375c5d22e_5a1f323ef56d − HTTP/3 w/ ECH
  • t13d1516h2_8daaf6152771_02713d6af862 − HTTP/2 w/ ECH
  • t13d1517h2_8daaf6152771_b0da82dd1658 − HTTP/2 w/ ECH
  • t13d1515h2_8daaf6152771_f37e75b10bcc − HTTP/2
  • t13d1516h2_8daaf6152771_9b887d9acb53 − HTTP/2

All these handshakes support post-quantum key agreements with a 1216 byte X25519MLKEM768 key. The first three listed JA4 fingerprints also use ECH.

JA4 fingerprint t13i010400_0f2cb44170f4_5c4c70b73fa0_518x136

Threat Intel and OSINT

CapLoader now matches network traffic against indicators of compromise (IOCs) from Johannes Bader's open source threat intelligence platform Rösti. An alert is raised whenever the analysed traffic matches any of the following IOC types on Rösti:

  • domain
  • domain:port
  • IP
  • IP:port

When a match occurs, CapLoader raises an alert on the flow/service and includes the matching IOC type and value. Rösti aggregates IOCs from public feeds, researchers, and threat‑intel providers (including IOCs published on this blog).

We have also extended the OSINT lookup shortcuts in CapLoader to include the following websites:

Right-click a flow/service/host/alert in CapLoader and select "Lookup [domain/IP/ASN] at...", which opens the chosen OSINT site in a browser tab with info about the domain/IP/ASN.

Encapsulated Protocols

CapLoader already decapsulates GRE, VXLAN, CapWap, Teredo, GTP-U, TZSP as well as IP-in-IP.

Decapsulate all the things

With this release we add support for extracting traffic from the following encapsulation protocols:

  • Aruba GRE encapsulated WiFi
  • Geneve (RFC 8926)
  • GRE in UDP (RFC 8086) to ports 4754 and 4755

Improved Protocol Detection

The precision of CapLoader's built-in port independent protocol identification has been improved and several additional protocols can now be detected, including GSocket, Hioles, Mirai, Pulsar RAT, PureRAT, SVCStealer and XenoRAT.

Posted by Erik Hjelmvik on Wednesday, 27 May 2026 09:15:00 (UTC/GMT)

Tags: #CapLoader #JA3 #JA4 #TLS #QUIC #OSINT #encapsulation #decapsulation #GRE

Short URL: https://netresec.com/?b=265c041


NetworkMiner 2.1 Released

NetworkMiner 2.1 Logo

We are releasing a new version of NetworkMiner today. The latest and greatest version of NetworkMiner is now 2.1.

Yay! /throws confetti in the air


Better Email Parsing

I have spent some time during 2016 talking to digital forensics experts at various law enforcement agencies. I learned that from time to time criminals still fail to use encryption when reading their email. This new release of NetworkMiner therefore comes with parsers for POP3 and IMAP as well as an improved SMTP parser. These are the de facto protocols used for sending and receiving emails, and have been so since way back in the 90’s.

Messages tab in NetworkMiner 2.1 showing extracted emails
Messages tab in NetworkMiner 2.1 showing extracted emails

Not only does NetworkMiner show the contents of emails within the tool, it also extracts all attachments to disk and even saves each email as an .eml file that can be opened in an external email reader in order to view it as the suspect would.

Extracted email Get_free_s.eml opened in Mozilla Thunderbird
Extracted email ”Get_free_s.eml” opened in Mozilla Thunderbird

Encapsulation Protocols

There are several protocols that can be used to provide logical separation of network traffic, in order to avoid using multiple physical networks to keep various network segments, security domains or users apart. Some of these techniques for logical separation rely on tagging or labeling, while others are tunneling the encapsulated traffic. Nevertheless, it’s all pretty much the same thing; an encapsulation protocol is used in order to wrap protocol X inside protocol Y, usually while adding some metadata in the process.

NetworkMiner has been able to parse the classic encapsulation protocols 802.1Q, GRE and PPPoE since 2011, but we now see an increased use of protocols that provide logical separation for virtualization and cloud computing environments. We have therefore added parsers in NetworkMiner 2.1 for VXLAN and OpenFlow, which are the two most widely used protocols for logical separation of traffic in virtualized environments. We have also added decapsulation of MPLS and EoMPLS (Ethernet-over-MPLS) to NetworkMiner 2.1.

Encapsulation examples for MPLS GRE and VXLAN

The new release additionally comes with support for the SOCKS protocol, which is an old school encapsulation protocol used by administrators as well as hackers in order to bypass firewalls or provide anonymous Internet access. The SOCKS parser in NetworkMiner can even be used to read network traffic from Tor in cleartext before it enters the Tor network. However, in order to capture Tor’s SOCKS traffic you’ll have to sniff traffic from the Tor client’s localhost interface on TCP port 9150.

PacketCache Logo

PacketCache

NetworkMiner 2.1 can read packets directly from a local PacketCache service by clicking ”File > Read from PacketCache”. This eliminates the need to run a PowerShell script in order to dump a PCAP file with packets recently captured by PacketCache.

HTTP Partial Content / Range Requests

Byte serving is a feature in HTTP that makes it possible to retrieve only a segment of a file, rather than the complete file, by using the “Range” HTTP header. This feature is often used by BITS in order to download updates for Windows. But we have also seen malware use byte serving, for example malware droppers that attempt to download malicious payloads in a stealthy manner. See Ursnif and Dridex for examples of malware that utilize this technique.

NetworkMiner has previously only reassembled the individual segments of a partial content download. But as of version 2.1 NetworkMiner has the ability to piece together the respective parts into a complete file.

SSL/TLS and X.509 Certificates

NetworkMiner has been able to extract X.509 certificates to disk for many years now, simply by opening a PCAP file with SSL traffic. However, in the 2.1 release we’ve added support for parsing out the SSL details also from FTP’s “AUTH TLS” (a.k.a explicit TLS or explicit SSL) and STARTTLS in SMTP.

NetworkMiner now also extracts details from the SSL handshake and X.509 certificate to the Parameters tab, such as the requested SNI hostname and the Subject CN from the certificate.

SSL and certificate information extracted by NetworkMiner from PCAP
SSL handshake details and certificate info passively extracted from captured HTTPS session to mega.co.nz

NetworkMiner Professional

The new features mentioned so far are all part of the free open source version of NetworkMiner. But we have also added a few additional features to the Professional edition of NetworkMiner as part of the 2.1 release.

The “Browsers” tab of NetworkMiner Professional has been extended with a feature for tracking online ads and web trackers. We are using EasyList and EasyPrivacy from easylist.to in order to provide an up-to-date tracking of ads and trackers. HTTP requests related to ads are colored red, while web tracker requests are blue. These colors also apply to the Files tab and can be modified in the Settings menu (Tools > Settings).

NetworkMiner Professional 2.1 showing Advertisments (red) and Trackers (blue)
NetworkMiner Professional 2.1 showing advertisments (red) and Internet trackers (blue).

The reason why NetworkMiner Pro now tracks ads and trackers is because these types of requests can make up almost half of the HTTP requests that a normal user makes while surfing the web today. Doing forensics on network traffic from a suspect criminal can be a very time consuming task, we therefore hope that being able to differentiate between what traffic that is initiated by the user rather than being triggered by an online advertisement service or internet tracker can save time for investigators.

The RIPE database previously contained a bug that prevented NetworkMiner Professional from properly leveraging netname info from RIPE. This bug has now been fixed, so that the Host Details can be enriched with details from RIPE for IP addresses in Europe. To enable the RIPE database you’ll first have to download the raw data by clicking Tools > Download RIPE DB.

Host Details with RIPE netname
Host Details enriched with RIPE description and netname

We have also extended the exported details about the hosts in the CSV and XML files from NetworkMiner Professional and the command line tool NetworkMinerCLI (available to users with a corporate license). The exported information now contains details such as IP Time-to-Live and open ports.

Upgrading to version 2.1

Users who have purchased a license for NetworkMiner Professional 2.0 can download a free update to version 2.1 from our customer portal.

Those who instead prefer to use the free and open source version can grab the latest version of NetworkMiner from the official NetworkMiner page.

Credits

There are several persons I would like to thank for contributing with feature requests and bug reports that have been used to improve NetworkMiner. I would like to thank Dietrich Hasselhorn, Christian Reusch, Jasper Bongertz, Eddi Blenkers and Daniel Spiekermann for their feedback that have helped improve the SMB, SMB2 and HTTP parsers as well as implementing various encapsulation protocols. I would also like to thank several investigators at the Swedish, German and Dutch police as well as EUROPOL for the valuable feedback provided by them.

Posted by Erik Hjelmvik on Wednesday, 11 January 2017 14:30:00 (UTC/GMT)

Tags: #NetworkMiner #POP3 #SMTP #IMAP #VXLAN #encapsulation #decapsulation #X.509 #PCAP

Short URL: https://netresec.com/?b=17124c4