ntop

How to Monitor What Matters
Yesterday we have been invited to the NetEye Users Group Meeting to give a speech about monitoring and cybersecurity. During the talk we covered out 25 years journey in this industry and the decisions we have made during that time: Network vendors provide (after 25 years) poor monitoring data: flaws, proprietary formats, sampling, device limitations didn’t change the landscape even though the NetFlow RFC 3954 is 20 years old, and IPFIX is basically just a cosmetic change. nDPI is 10 years old and it allowed us to provide contextual information …
ntop

Announcing ntop Professional Training: November 2023
ntop tools range from packet capture, traffic analysis and processing, and sometimes it is not easy to keep up on product updates as well master all the tools. This has been the driving force for organising ntop professional training: . This is to announce that in May we have scheduled the next ntop Professional Training session. It will take place online (Microsoft Teams) on 7th, 9th, 14th, 16th, 21st, 23rd of November, 2023 at 3.00 PM CET (9.00 AM EDT). Training will be held in English language and each session …
ntopng

How to Send ntopng Alerts to PagerDuty
PagerDuty is a popular incident-response platform that allows problem notifications to be delivered in a flexible way to the correct team member. We have integrated it in ntopng Enterprise and this post shows you howto configure it. First of all you need to create a PagerDuty account and select a plan (there is a free one you can choose). Done that within PagerDuty you need to select “Event Orchestration” from the “Automation” menu and create a new event orchestration. Below you can see an example. Once you saved it click …
nDPI

How nDPI Improved Bloom Filters Implementation
A Bloom filter is. probabilistic data-structure used to test whether an element is present in a set. Blooms are affected by false positives, meaning that when a bloom returns true it does not mean that the searched element is part of the set but that it is “likely” to be part of the set. nDPI (and most tools ntop develops) uses Bloom filters in order to speed-up search operations by using a quick membership check that avoids slower checks. For instance if ntopng needs to know whether host A has …
Features

How we Improved Alarm Delivery in ntopng
Sometimes, a critical issue shows up in your network and you’d like to be notified by ntopng on Telegram or by E-Mail. ntopng allows you to filter alerts for each recipient based on a few criteria including alert family, category, severity, or affected hosts. However in some case you want to be notified about a very specific alert, out of all alerts produced with the same family, category, severity. For example, it’s important to be notified when an Interface has no traffic, or when a new device (MAC) connects or …
ntop

Introducing PF_RING 8.6: Runtime Filtering and On Demand IDS at 100 Gbit
This is to announce a new PF_RING release 8.6 ! This stable release introduces a new Runtime component in PF_RING, which adds support for runtime filtering. This allows an external application to push filtering rules (through a Redis queue) while the socket is running, and offload them to the adapter when supported (e.g. on NVIDIA/Mellanox Connect-X adapters). This enables Zeek and Suricata “on-demand” at 100 Gbit as discussed in a previous post. This release also adds support for Debian 12 and latest 6.x kernel shipped with Ubuntu 22 LTS. Many other improvements …
ntop

Sorting Out and Clustering Alerts in ntopng
In a previous post, What’s In The (Alert) Inbox?, we’ve discussed how alerts are organised in the Alerts Explorer. The new “inbox” design allows us to cluster alerts into separate folders high-priority events, that require attention and needs to be addresses as soon as possible, from other minor events. This solves one issue: having all critical alerts under control, while still tracking and archiving all minor Network issues (that contribute to the hosts score, and may be still of interest when drilling down during our analysis). In a system which …
ntop

What’s In The (Alert) Inbox?
ntopng emits alerts in order to report relevant. They can be triggered by traffic thresholds, user scripts, behavioural checks, or due to Security issues, including those detected by IDS systems integrated with ntopng (the full list of built-in checks, and related alerts, that can be enabled in ntopng is available in the Alerts section of the documentation). Sometimes they are really critical and should be handled immediately to fix the problem, this is the case of Security events for instance (e.g. a compromised host that must be sanitized as soon as …
Cybersecurity

How Effective Are IP Blacklists When Used For Detecting Malicious Activities?
A blacklist is an access control mechanism which denies access to selected network resources to peers belonging to a curated list. Blacklists often represent the first line of defence for many networks as they can reduce internal hosts’ risk of establishing communications with peers with a bad reputation. Many companies use blacklists for detecting malicious activities. In ntopng we use IP blacklists to label traffic exchanged with malicious peers. While the concept of blacklist is very simple and many people are familiar with it, we know very little of how …
nDPI

How nDPI Identifies Fully Encrypted Protocols
In the paper How the Great Firewall of China Detects and Blocks Fully Encrypted Traffic it is described a technique used in censorship to identify and block fully encrypted protocols. This technique, limited to TCP flows, uses a few techniques that are applied on the first TCP packet with payload, making it fast and convenient although with a small (< 1%)  percentage of false positives: Ex1: popcount(pkt) ≤ 3.4 or popcount(pkt) ≥ 4.6. len(pkt) len(pkt) Ex2: The first six (or more) bytes of pkt are [0x20, 0x7e]. Ex3: More than …
ntopng

Understanding Timeseries Throughput Calculation
ntopng creates timeseries for traffic by periodically (e.g. every minute) writing into RRD/Influx the traffic volume observed. Below you can see an example. Traffic is used to keep track of the data volume exchanged. Over time timeseries are aggregated (roll-up) to save space, meaning for instance that 60 minute observations are used to compute a hourly observation. A timeseries rollup involves summarising the original time series data over larger time intervals. The purpose of doing a rollup is to reduce the volume of data and make it more manageable while …
ntopng

HowTo Trigger an Alert When Contacting a Website/IP with ntopng
ntopng has native blacklist support that enables generation of alerts when malware sites are contacted. You can enable/disable the list of active blacklist by accessing the blacklist page from the preferences menu of the left sidebar and also configure the list properties such as refresh rate as well enable/disable them. Now suppose you want to trigger an alert when contacting a specific IP address or a website (this regardless if using clear-text protocol such as HTTP or encrypted TLS-based communications). How can you do that? See it below: Define a …

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