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The Hacker News - Cybersecurity News and Analysis: Search results for DNS resolver

New DNS Vulnerability Lets Attackers Launch Large-Scale DDoS Attacks

New DNS Vulnerability Lets Attackers Launch Large-Scale DDoS Attacks

May 20, 2020Ravie Lakshmanan
Israeli cybersecurity researchers have disclosed details about a new flaw impacting DNS protocol that can be exploited to launch amplified, large-scale distributed denial-of-service (DDoS) attacks to takedown targeted websites. Called NXNSAttack , the flaw hinges on the DNS delegation mechanism to force DNS resolvers to generate more DNS queries to authoritative servers of attacker's choice, potentially causing a botnet-scale disruption to online services. "We show that the number of DNS messages exchanged in a typical resolution process might be much higher in practice than what is expected in theory, mainly due to a proactive resolution of name-servers' IP addresses," the researchers said in the paper. "We show how this inefficiency becomes a bottleneck and might be used to mount a devastating attack against either or both, recursive resolvers and authoritative servers." Following responsible disclosure of NXNSAttack, several of the companies i
NSA Suggests Enterprises Use 'Designated' DNS-over-HTTPS' Resolvers

NSA Suggests Enterprises Use 'Designated' DNS-over-HTTPS' Resolvers

January 15, 2021Ravie Lakshmanan
The U.S. National Security Agency (NSA) on Friday said DNS over HTTPS (DoH) — if configured appropriately in enterprise environments — can help prevent "numerous" initial access, command-and-control, and exfiltration techniques used by threat actors. "DNS over Hypertext Transfer Protocol over Transport Layer Security (HTTPS), often referred to as DNS over HTTPS (DoH), encrypts DNS requests by using HTTPS to provide privacy, integrity, and 'last mile' source authentication with a client's DNS resolver," according to the NSA's  new guidance . Proposed in 2018,  DoH  is a protocol for performing remote Domain Name System resolution via the HTTPS protocol. One of the major shortcomings with current DNS lookups is that even when someone visits a site that uses HTTPS, the DNS query and its response is sent over an unencrypted connection, thus allowing third-party eavesdropping on the network to track every website a user is visiting. Even worse, the
New Side Channel Attacks Re-Enable Serious DNS Cache Poisoning Attacks

New Side Channel Attacks Re-Enable Serious DNS Cache Poisoning Attacks

November 18, 2021Ravie Lakshmanan
Researchers have demonstrated yet another variant of the SAD DNS cache poisoning attack that leaves about 38% of the domain name resolvers vulnerable, enabling attackers to redirect traffic originally destined to legitimate websites to a server under their control. "The  attack  allows an off-path attacker to inject a malicious DNS record into a DNS cache," University of California researchers Keyu Man, Xin'an Zhou, and Zhiyun Qian  said . "SAD DNS attack allows an attacker to redirect any traffic (originally destined to a specific domain) to his own server and then become a man-in-the-middle (MITM) attacker, allowing eavesdropping and tampering of the communication." The latest flaw affects Linux kernels as well as popular DNS software, including BIND, Unbound, and dnsmasq running on top of Linux, but not when run on other operating systems FreeBSD or Windows. From Kaminsky Attack to SAD DNS DNS cache poisoning, also called DNS spoofing, is a  technique  i
A Set of Severe Flaws Affect Popular DNSMasq DNS Forwarder

A Set of Severe Flaws Affect Popular DNSMasq DNS Forwarder

January 19, 2021Ravie Lakshmanan
Cybersecurity researchers have uncovered multiple vulnerabilities in Dnsmasq, a popular open-source software used for caching Domain Name System (DNS) responses, thereby potentially allowing an adversary to mount DNS  cache poisoning attacks  and remotely execute malicious code. The seven flaws, collectively called " DNSpooq " by Israeli research firm JSOF, echoes previously disclosed weaknesses in the DNS architecture, making Dnsmasq servers powerless against a range of attacks. "We found that Dnsmasq is vulnerable to DNS cache poisoning attack by an off-path attacker (i.e., an attacker that does not observe the communication between the DNS forwarder and the DNS server)," the researchers noted in a report published today. "Our attack allows for poisoning of multiple domain names at once, and is a result of several vulnerabilities found. The attack can be completed successfully under seconds or few minutes, and have no special requirements. We also found
How to Make Your Internet Faster with Privacy-Focused 1.1.1.1 DNS Service

How to Make Your Internet Faster with Privacy-Focused 1.1.1.1 DNS Service

April 02, 2018Mohit Kumar
Cloudflare, a well-known Internet performance and security company, announced the launch of 1.1.1.1 —world's fastest and privacy-focused secure DNS service that not only speeds up your internet connection but also makes it harder for ISPs to track your web history. Domain Name System (DNS) resolver, or recursive DNS server, is an essential part of the internet that matches up human-readable web addresses with their actual location on the internet, called IP addresses. For example, when you try to open a website, say thehackernews.com, your DNS looks up for the IP address linked to this domain name and load the site. Since the default DNS services provided by ISPs are often slow and insecure, most people rely on alternative DNS providers—such as OpenDNS (208.67.222.222), Comodo DNS (8.26.56.26) and Google (8.8.8.8), to speed up their Internet. But if you use Cloudflare new 1.1.1.1 DNS service , your computer/smartphone/tablet will start resolving domain names within a bla
SAD DNS — New Flaws Re-Enable DNS Cache Poisoning Attacks

SAD DNS — New Flaws Re-Enable DNS Cache Poisoning Attacks

November 12, 2020Ravie Lakshmanan
A group of academics from the University of California and Tsinghua University has uncovered a series of critical security flaws that could lead to a revival of DNS cache poisoning attacks. Dubbed " SAD DNS attack " (short for Side-channel AttackeD DNS), the technique makes it possible for a malicious actor to carry out an off-path attack, rerouting any traffic originally destined to a specific domain to a server under their control, thereby allowing them to eavesdrop and tamper with the communications. "This represents an important milestone — the first weaponizable network side channel attack that has serious security impacts," the researchers said. "The attack allows an off-path attacker to inject a malicious DNS record into a DNS cache." Tracked as CVE-2020-25705, the findings were presented at the ACM Conference on Computer, and Communications Security (CCS '20) held this week. The flaw affects operating systems Linux 3.18-5.10, Windows Serv
Google DNS Service (8.8.8.8) Now Supports DNS-over-TLS Security

Google DNS Service (8.8.8.8) Now Supports DNS-over-TLS Security

January 10, 2019Swati Khandelwal
Almost every activity on the Internet starts with a DNS query, a key function of the Internet that works as an Internet's directory where your device looks up for the server IP addresses after you enter a human-readable web address (e.g., thehackernews.com). Since DNS queries are sent in clear text over UDP or TCP without encryption, the information can reveal not only what websites an individual visits but is also vulnerable to spoofing attacks. To address these problems, Google announced Wednesday that its Public DNS (Domain Name System) service finally supports DNS-over-TLS security protocol, which means that the DNS queries and responses will be communicated over TLS-encrypted TCP connections. The DNS-over-TLS has been designed to make it harder for man-in-the-middle attackers to manipulate the DNS query or eavesdrop on your Internet connection. Launched over eight years ago, Google Public DNS, at IP addresses 8.8.8.8 and 8.8.4.4, is world's largest public Domai
New TsuNAME Flaw Could Let Attackers Take Down Authoritative DNS Servers

New TsuNAME Flaw Could Let Attackers Take Down Authoritative DNS Servers

May 07, 2021Ravie Lakshmanan
Security researchers Thursday disclosed a new critical vulnerability affecting Domain Name System (DNS) resolvers that could be exploited by adversaries to carry out reflection-based denial-of-service attacks against authoritative nameservers. The flaw, called  'TsuNAME ,' was discovered by researchers from SIDN Labs and InternetNZ, which manage the national top-level internet domains '.nl' and '.nz' for the Netherlands and New Zealand, respectively. "TsuNAME occurs when domain names are misconfigured with cyclic dependent DNS records, and when vulnerable resolvers access these misconfigurations, they begin looping and send DNS queries rapidly to authoritative servers and other resolvers," the researchers said. A recursive DNS resolver is one of the core components involved in  DNS resolution , i.e., converting a hostname such as www.google.com into a computer-friendly IP address like 142.250.71.36. To achieve this, it responds to a client's r
Microsoft Releases Windows Update (Dec 2020) to Fix 58 Security Flaws

Microsoft Releases Windows Update (Dec 2020) to Fix 58 Security Flaws

December 08, 2020Ravie Lakshmanan
Microsoft on Tuesday released fixes for 58 newly discovered security flaws spanning as many as 11 products and services as part of its final  Patch Tuesday of 2020 , effectively bringing their CVE total to 1,250 for the year. Of these 58 patches, nine are rated as Critical, 46 are rated as Important, and three are rated Moderate in severity. The December security release addresses issues in Microsoft Windows, Edge browser, ChakraCore, Microsoft Office, Exchange Server, Azure DevOps, Microsoft Dynamics, Visual Studio, Azure SDK, and Azure Sphere. Fortunately, none of these flaws this month have been reported as publicly known or being actively exploited in the wild. The fixes for December concern a number of remote code execution (RCE) flaws in Microsoft Exchange (CVE-2020-17132), SharePoint (CVE-2020-17118 and CVE-2020-17121), Excel (CVE-2020-17123), and Hyper-V virtualization software (CVE-2020-17095), as well as a patch for a security feature bypass in Kerberos (CVE-2020-16996)
World's biggest DDoS attack that Almost Broke the Internet

World's biggest DDoS attack that Almost Broke the Internet

March 29, 2013Mohit Kumar
The last week has seen probably the largest distributed denial-of-service (DDoS) attack ever. A massive 300Gbps was thrown against Internet blacklist maintainer Spamhaus' website but the anti-spam organisation , CloudFlare was able to recover from the attack and get its core services back up and running.  Spamhaus, a group based in both London and Geneva, is a non-profit organisation that aims to help email providers filter out spam and other unwanted content. Spamhaus is pretty resilient, as its own network is distributed across many countries, but the attack was still enough to knock its site offline on March 18. Five national cyber-police-forces are investigating the attacks.  A group calling itself STOPhaus,  an alliance of hactivists and cyber criminals is believed to responsible for bombarding Spamhaus with up to 300Gbps. The attacks on Spamhaus illustrate a larger problem with the vulnerability of systems fundamental to the architecture of the Internet, the D
CVE-2012-2808 : Android 4.0.4 DNS poisoning vulnerability Exposed

CVE-2012-2808 : Android 4.0.4 DNS poisoning vulnerability Exposed

July 24, 2012Mohit Kumar
Android's DNS resolver is vulnerable to DNS poisoning due to weak randomness in its implementation. Researchers Roee Hay & Roi Saltzman from IBM Application Security Research Group demonstrate that how an attacker can successfully guess the nonce of the DNS request with a probability thatis su cient for a feasible attack. Android version 4.0.4 and below are Vulnerable to this bug. Weakness in its pseudo-random number generator (PRNG), which makes DNS poisoning attacks feasible. DNS poisoning attacks may endanger the integrity and con dentiality of the attacked system. For example, in Android, the Browser app can be attacked in order to steal the victim's cookies of a domain of the attacker's choice. If the attacker manages to lure the victim to browse to a web page controlled by him/her, the attacker can use JavaScript, to start resolving non-existing sub-domains. Upon success, a sub-domain points to the attacker's IP, which enables the latter to steal wild card
New Browser Attack Allows Tracking Users Online With JavaScript Disabled

New Browser Attack Allows Tracking Users Online With JavaScript Disabled

March 11, 2021Ravie Lakshmanan
Researchers have discovered a new side-channel that they say can be reliably exploited to leak information from web browsers that could then be leveraged to track users even when JavaScript is completely disabled. "This is a side-channel attack which doesn't require any JavaScript to run," the researchers said. "This means script blockers cannot stop it. The attacks work even if you strip out all of the fun parts of the web browsing experience. This makes it very difficult to prevent without modifying deep parts of the operating system." In avoiding JavaScript, the side-channel attacks are also architecturally agnostic, resulting in microarchitectural website fingerprinting attacks that work across hardware platforms, including Intel Core, AMD Ryzen, Samsung Exynos 2100, and Apple M1 CPUs — making it the first known side-channel attack on the iPhone maker's new ARM-based chipsets. The  findings , which come from a group of academics from the Ben-Gurion U
Critical glibc Flaw Puts Linux Machines and Apps at Risk (Patch Immediately)

Critical glibc Flaw Puts Linux Machines and Apps at Risk (Patch Immediately)

February 17, 2016Swati Khandelwal
A highly critical vulnerability has been uncovered in the GNU C Library (glibc) , a key component of most Linux distributions, that leaves nearly all Linux machines, thousands of apps and electronic devices vulnerable to hackers that can take full control over them. Just clicking on a link or connecting to a server can result in remote code execution (RCE), allowing hackers to steal credentials, spy on users, seize control of computers, and many more. The vulnerability is similar to the last year's  GHOST vulnerability (CVE-2015-0235) that left countless machines vulnerable to remote code execution (RCE) attacks , representing a major Internet threat. GNU C Library (glibc) is a collection of open source code that powers thousands of standalone apps and most Linux distributions, including those distributed to routers and other types of hardware. The recent flaw, which is indexed as CVE-2015-7547 , is a stack-based buffer overflow vulnerability in glibc's D
Millions of WordPress sites exploitable for DDoS Attacks using Pingback mechanism

Millions of WordPress sites exploitable for DDoS Attacks using Pingback mechanism

May 01, 2013Mohit Kumar
Distributed Denial of Service attacks have increased in scale, intensity and frequency. The wide range of motives for these attacks political , criminal, or social makes every merchant or organization with an online presence a potential target. Over the weekend Incapsula mitigated a unique DDoS attack against a large gaming website, in which they have discovered a DDoS attack using thousands of legitimate WordPress blogs without the need for them to be compromised. Incapsula released the list of approximately 2,500 WordPress sites from where the attack was originated, including some very large sites like Trendmicro.com, Gizmodo.it and Zendesk.com . In a recent report , we posted about another method for DDoS attacks using DNS amplification , where a DNS request is made to an open DNS resolver with the source IP address forged so that it is the IP address of the targeted site to which the response is thus sent, but this new method uses HTTP rather than DNS. The
Knock v1.5 - Subdomain Scanner , allows to bypass wildcard

Knock v1.5 - Subdomain Scanner , allows to bypass wildcard

August 24, 2011Mohit Kumar
Knock v1.5  - Subdomain Scanner , allows to bypass wildcard Knock is a python script, written by Gianni 'guelfoweb' Amato, designed to enumerate subdomains on a target domain through a wordlist. This program is self contained, doesn't need to be installed in any particular location. All it needs is a recent version of Python 2.xOnly for use the Zone Transfer option (-zt) you must install the module dnspython, otherwise you can do without. If the name server allows zone transfers to occur, all the DNS names and IP addresses hosted by the name server will be returned in human-readable ASCII text. Usage $ python knock.py <option> <url> Rapid Scan Scanning with internal wordlist: $ python knock.py <url> Scanning with external wordlist: $ python knock.py <url> <wordlist> Options -zt Zone Transfer discovery: $ python knock.py -zt <url> -dns Dns resolver: $ python knock.py -dns <url> -wc Wildcard testing: $ python knock.py
New Ripple20 Flaws Put Billions of Internet-Connected Devices at Risk of Hacking

New Ripple20 Flaws Put Billions of Internet-Connected Devices at Risk of Hacking

June 16, 2020Mohit Kumar
The Department of Homeland Security and CISA ICS-CERT today issued a critical security advisory warning about over a dozen newly discovered vulnerabilities affecting billions of Internet-connected devices manufactured by many vendors across the globe. Dubbed " Ripple20 ," the set of 19 vulnerabilities resides in a low-level TCP/IP software library developed by Treck, which, if weaponized, could let remote attackers gain complete control over targeted devices—without requiring any user interaction. According to Israeli cybersecurity company JSOF—who discovered these flaws—the affected devices are in use across various industries, ranging from home/consumer devices to medical, healthcare, data centers, enterprises, telecom, oil, gas, nuclear, transportation, and many others across critical infrastructure. "Just a few examples: data could be stolen off of a printer, an infusion pump behavior changed, or industrial control devices could be made to malfunction. An
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