NETRESEC Network Security Blog - Tag : VoIP

NetworkMiner 2.3.2 Released!

NetworkMiner 2.3.2 was released this morning, and there was much rejoicing!

Image: U.S. Navy photo by Stuart Phillips (source)

This new release primarily fixes bugs related to extraction of emails and VoIP calls. We have also corrected a bug affecting the json/CASE export function in NetworkMiner Professional.

The OSINT domain name lookup in NetworkMiner Professional has also been extended with the Certificate Search and DNSTrails has been replaced with SecurityTrails.

NetworkMiner Professional 2.3.2 Image: NetworkMiner Professional 2.3.2 with “vm_win7.pcap” from University of Twente’s Data Exfiltration Malware dataset loaded.


NetworkMiner 2.3.2

We’d like to thank Carlos Kasprzykowski for notifying us about the VoIP bug, which caused lots of files to be written to the %TEMP% directory when there were more than 50 simultaneous SIP+RTP calls. We also wanna thank Josh Wilczek for reporting a bug in the “User Defined Port-to-Protocol Mappings” in NetworkMiner Professional’s Settings window, which also has been fixed in the 2.3.2 release.

Upgrading to Version 2.3.2

Users who have purchased a license for NetworkMiner Professional 2.x can download a free update to version 2.3.2 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.


Posted by Erik Hjelmvik on Monday, 27 August 2018 09:23:00 (UTC/GMT)

Tags: #Netresec #NetworkMiner #RTP #VoIP #SIP #email #CASE

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NetworkMiner 2.3 Released!

The free and open source network forensics tool NetworkMiner now comes with improved extraction of files and metadata from several protocols as well as a few GUI updates. But the biggest improvements for version 2.3 are in the commercial tool NetworkMiner Professional, which now supports VoIP call audio extraction and playback as well as OSINT lookups of file hashes, IP addresses, domain names and URLs.

I’m happy to announce that NetworkMiner 2.3 now does an even better job than before at extracting files and metadata from several protocols. Improvements have been made in the parsers for the following protocols: HTTP, IEC-104, IPv4, Modbus, SIP, SMB, SMB2, SMTP and SSL/TLS.

We have also added support for the SNMP protocol in NetworkMiner 2.3, so that SNMP community strings can be extracted and displayed on the Parameters and Credentials tabs.

SNMP Community Strings in NetworkMiner's Credential tab

Another change is that timestamps are now displayed using the UTC time zone instead of using the local time zone. We have also fixed a few GUI quirks in order to further improve the usability of the tool.

NetworkMiner Professional

The commercial version of NetworkMiner, i.e. NetworkMiner Professional, comes with several additional improvements which are presented below.

VoIP Call Playback

NetworkMiner Professional has received a new tab called “VoIP”, which enables audio playback of VoIP calls that are using SIP and RTP with G.711 μ-law or A-law encoding (u-Law is primarily used in North America and Japan while A-law is used in Europe and most other parts of the world).

Video: Audio playback and extraction to WAV from the “SIP_CALL_RTP_G711” PCAP file in the Wireshark Sample Captures.

The audio streams from the VoIP calls are also extracted to disk as .WAV files when codecs G.729 or G.711 (u-Law and A-Law) is used. NetworkMiner Professional also attempts to reassemble RTP streams encoded with G.722 to .au files.

OSINT Lookups of IP Addresses, Domains, URLs and File Hashes

Right-clicking a network host in NetworkMiner Professional’s Hosts tab brings up a context menu with options for performing lookups of IP and domain names using external sources. We refer to this method as open-source intelligence (OSINT) because the accessed data resides at publicly available sources.

OSINT IP lookup in NetworkMiner Professional 2.3

Clicking on an OSINT provider brings up a webpage with more detailed information about the selected IP address, such as IBM X-Force, mnemonic Passive DNS, Shodan, UrlQuery or VT. However, if you’re lazy like me, then you’ll probably click the “All above!” option instead, which will bring up all of the sources in separate tabs in your browser.

The full list of OSINT providers available for IP lookups includes APNIC Whois, BFK Passive DNS, Censys, Cymon, DNSTrails, ExoneraTor, Google Public DNS,, Hurricane Electric, IBM X-Force, Internet Storm Center, mnemonic Passive DNS, PacketTotal, Shodan, ThreatCrowd, ThreatMiner, UrlQuery and VirusTotal.

The domain name lookup menu contains a similar set of providers: BFK Passive DNS, Cymon, DNSTrails, Google Public DNS, Google Safe Browsing, Hybrid Analysis, IBM X-Force Exchange, mnemonic Passive DNS, MXToolBox, MyWOT, Norton Safe Web, PacketTotal, ThreatCrowd, ThreatMiner, URL Void, UrlQuery, VirusTotal, Website Informer, Webutation and Whoisology.

OSINT URL lookup in NetworkMiner Professional 2.3

Right-clicking a URL in the Browsers tab brings up a similar context menu, which additionally includes the following services for URL lookups: Google Safe Browsing, IBM X-Force, ThreatMiner, URLhaus and UrlQuery.

OSINT file hash lookup in NetworkMiner Professional 2.3

Finally, right-clicking on one of the files that NetworkMiner has extracted from a PCAP file brings up a menu for doing OSINT lookups based on the MD5 or SHA256 hash of the file. The sources used for lookups of hashes include IBM X-Force, PacketTotal, ThreatCrowd, TotalHash, UrlQuery,, Comodo Valkyrie, AlienVault OTX, Hybrid Analysis, ThreatMiner and VirusTotal.

Hybrid Analysis API Integration

Did you know that the malware analysis service Hybrid Analysis provides free API keys to people in the IT security community?

@HybridAnalysis: We are excited to announce that full API keys for file submissions are now available to everyone of the IT security community

This is a great move by the Hybrid Analysis team, and we’re happy to announce that we have leveraged their API in NetworkMiner Professional in order to submit files for analysis directly from within the NetworkMiner GUI. The API integration also enables you to query for an IP on Hybrid Analysis to see which previously submitted samples has communicated with that particular IP address.

Here are the steps required to enable the Hybrid Analysis API integration:


I would like to thank Chris Sistrunk, Mats Karlsson and Michael Nilsson for suggesting several of the protocol and GUI improvements that have been incorporated into this new release. I’d also like to thank Doug Green and Ahmad Nawawi for discovering and reporting bugs in the IP and SSL parser respectively.

Upgrading to Version 2.3

Users who have purchased a license for NetworkMiner Professional 2.x can download a free update to version 2.3 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.


Posted by Erik Hjelmvik on Tuesday, 03 April 2018 06:27:00 (UTC/GMT)

Tags: #NetworkMiner #PCAP #OSINT #SMTP #SIP #RTP #VoIP #Network Forensics #extract #Netresec

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Port Independent Protocol Detection

Protocol Alphabet Soup by ThousandEyes

Our heavy-duty PCAP analyzer CapLoader comes with a feature called ”Port Independent Protocol Identification”, a.k.a. PIPI (see Richard Bejtlich's PIPI blog post from 2006). Academic research in the Traffic Measurement field often use the term ”Traffic Classification”, which is similar but not the same thing. Traffic Classification normally group network traffic in broad classes, such as Email, Web, Chat or VoIP. CapLoader, on the other hand, identifies the actual application layer protocol used in each flow. So instead of classifying a flow as ”VoIP” CapLoader will tell you if the flow carries SIP, Skype, RTP or MGCP traffic. This approach is also known as “Dynamic Protocol Detection”.

Being able to identify application layer protocols without relying on the TCP or UDP port number is crucial when analyzing malicious traffic, such as malware Command-and-Control (C2) communication, covert backdoors and rouge servers, since such communication often use services on non-standard ports. Some common examples are:

  • Many botnet C2 protocols communicate over port TCP 443, but using a proprietary protocol rather than HTTP over SSL.
  • Backdoors on hacked computers and network devices typically wither run a standard service like SSH on a port other than 22 in order to hide.
  • More advanced backdoors use port knocking to run a proprietary C2 protocol on a standard port (SYNful knock runs on TCP 80).

This means that by analyzing network traffic for port-protocol anomalies, like an outgoing TCP connection to TCP 443 that isn't SSL, you can effectively detect intrusions without having IDS signatures for all C2 protocols. This analysis technique is often used when performing Rinse-Repeat Intrusion Detection, which is a blacklist-free approach for identifying intrusions and other form of malicious network traffic. With CapLoader one can simply apply a BPF filter like “port 443” and scroll through the displayed flows to make sure they are all say “SSL” in the Protocol column.

CapLoader detects non-SSL traffic to Image: Miuref/Boaxxe Trojan C2 traffic to "1.web-counter[.]info" on TCP 443 doesn't use SSL (or HTTPS)

Statistical Analysis

CapLoader relies on statistical analysis of each TCP, UDP and SCTP session's behavior in order to compare it to previously computed statistical models for known protocols. These statistical models are generated using a multitude of metrics, such as inter-packet delays, packet sizes and payload data. The port number is, on the other hand, a parameter that is intentionally not used by CapLoader to determine the application layer protocol.

The PIPI/Dynamic Protocol Detection feature in CapLoader has been designed to detect even encrypted and obfuscated binary protocols, such as Tor and Encrypted BitTorrent (MSE). These protocols are designed in order to deceive protocol detection mechanisms, and traditional signature based protocol detection algorithms can't reliably detect them. The statistical approach employed by CapLoader can, on the other hand, actually detect even these highly obfuscated protocols. It is, however, important to note that being a statistical method it will never be 100% accurate. Analysts should therefore not take for granted that a flow is using the protocol stated by CapLoader. There are some situations when it is very difficult to accurately classify an encrypted protocol, such as when the first part of a TCP session is missing in the analyzed data. This can occur when there is an ongoing session that was established before the packet capture was started.

Identified Protocols

The following protocols are currently available for detection in CapLoader's protocol database:

AOL Instant Messenger
BitTorrent Encrypted - MSE
DropBox LSP
eDonkey Obfuscated
Gh0st RAT
Groove LAN DPP
MikroTik NDP
Modbus TCP
MSN Messenger
NetBIOS Datagram Service
NetBIOS Name Service
NetBIOS Session Service
Poison Ivy RAT
Reverse Shell
SopCast P2P
Spotify P2P
Spotify Server
TeamViewer UDP
XMPP Jabber
Zeus TCP
Zeus UDP

The list of implemented protocols is constantly being increased with new protocols.

PIPI in NetworkMiner

NetworkMiner Logo

NetworkMiner Professional, which is the commercial version of NetworkMiner, also comes with an implementation of our protocol detection mechanism. Even though NetworkMiner Professional doesn't detect as many protocols as CapLoader, the PIPI feature built into NetworkMiner Pro still helps a lot when analyzing HTTP traffic on ports other that 80 or 8080 as well as in order to reassemble files downloaded from FTP or TFTP servers running on non-standard ports.


Posted by Erik Hjelmvik on Tuesday, 06 October 2015 09:05:00 (UTC/GMT)

Tags: #Protocol Identification #CapLoader #VoIP #SIP #RTP #TOR #SSL #PIPI #PCAP #NetworkMiner

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Recommended Books

» The Practice of Network Security Monitoring, Richard Bejtlich (2013)

» Applied Network Security Monitoring, Chris Sanders and Jason Smith (2013)

» Network Forensics, Sherri Davidoff and Jonathan Ham (2012)

» The Tao of Network Security Monitoring, Richard Bejtlich (2004)

» Practical Packet Analysis, Chris Sanders (2017)

» Windows Forensic Analysis, Harlan Carvey (2009)

» TCP/IP Illustrated, Volume 1, Kevin Fall and Richard Stevens (2011)

» Industrial Network Security, Eric D. Knapp and Joel Langill (2014)