Web cache poisoning

Explanation: Web cache poisoning is a complicated technique whereby an attacker
exploits the behavior of an internet server and cache in order that a harmful HTTP
response is served to other users.Fundamentally, web cache poisoning involves two
phases. First, the attacker must compute the way to elicit a response from the back-end
server that inadvertently contains some quite dangerous payload. Once successful, they
have to form sure that their response is cached and subsequently served to the intended
victims.A poisoned web cache can potentially be a devastating means of distributing
numerous different attacks, exploiting vulnerabilities like XSS, JavaScript injection, open
redirection, and so on.
How does an internet cache work?To understand how web cache poisoning vulnerabilities
arise, it’s important to possess a basic understanding of how web caches work.If a server
had to send a replacement response to each single HTTP request separately, this is able
to likely overload the server, leading to latency issues and a poor user experience,
especially during busy periods. Caching is primarily a way of reducing such issues.The
cache sits between the server and therefore the user, where it saves (caches) the
responses to particular requests, usually for a hard and fast amount of your time . If
another user then sends the same request, the cache simply serves a replica of the cached
response on to the user, with none interaction from the back-end. This greatly eases the
load on the server by reducing the amount of duplicate requests it’s to handle.
Cache keysWhen the cache receives an HTTP request, it first has got to determine
whether there’s a cached response that it can serve directly, or whether it’s to forward the
request for handling by the back-end server. Caches identify equivalent requests by
comparing a predefined subset of the request’s components, known collectively because
the “cache key”. Typically, this is able to contain the request line and Host header.
Components of the request that aren’t included within the cache key are said to be
“unkeyed”.If the cache key of an incoming request matches the key of a previous request,
then the cache considers them to be equivalent. As a result, it’ll serve a replica of the
cached response that was generated for the first request. this is applicable to all or any
subsequent requests with the matching cache key, until the cached response
expires.Crucially, the opposite components of the request are ignored altogether by the
cache. We’ll explore the impact of this behavior in additional detail later.
What is the impact of an internet cache poisoning attack?The impact of web cache
poisoning is heavily hooked in to two key factors:• What precisely the attacker can
successfully get cachedAs the poisoned cache is more a way of distribution than a
standalone attack, the impact of web cache poisoning is inextricably linked to how harmful
the injected payload is. like most sorts of attack, web cache poisoning also can be utilized
in combination with other attacks to escalate the potential impact even further.• The
quantity of traffic on the affected pageThe poisoned response will only be served to users
who visit the affected page while the cache is poisoned. As a result, the impact can range
from non-existent to massive counting on whether the page is popular or not. If an attacker
managed to poison a cached response on the house page of a serious website, for
instance , the attack could affect thousands of users with none subsequent interaction from
the attacker.Note that the duration of a cache entry doesn’t necessarily affect the impact of
web cache poisoning. An attack can usually be scripted in such how that it re-poisons the

filetype

Make sure that legitimate network routers are configured to run routing protocols with authentication.

Grey-box

Blind SQL injection

Nmap

Harden DNS servers

Use split-horizon operation for DNS servers

Restrict Zone transfers

Have subnet diversity between DNS servers

MS Blaster

http-methods

False

VRFY

Explanation: The VRFY commands enables SMTP clients to send an invitation to an
SMTP server to verify that mail for a selected user name resides on the server. The VRFY
command is defined in RFC 821.The server sends a response indicating whether the user
is local or not, whether mail are going to be forwarded, and so on. A response of 250
indicates that the user name is local; a response of 251 indicates that the user name isn’t
local, but the server can forward the message. The server response includes the mailbox
name.

Wireless sniffing

A wireless sniffer may be a sort of packet analyzer. A packet analyzer (also referred to as a
packet sniffer) may be a piece of software or hardware designed to intercept data because
it is transmitted over a network and decode the info into a format that’s readable for
humans. Wireless sniffers are packet analyzers specifically created for capturing data on
wireless networks. Wireless sniffers also are commonly mentioned as wireless packet
sniffers or wireless network sniffers.Wireless sniffer tools have many uses in commercial IT
environments. Their ability to watch , intercept, and decode data because it is in transit
makes them useful for:• Diagnosing and investigating network problems• Monitoring
network usage, activity, and security• Discovering network misuse, vulnerabilities, malware,
and attack attempts• Filtering network traffic• Identifying configuration issues and network
bottlenecks• Wireless Packet Sniffer AttacksWhile wireless packet sniffers are valuable
tools for maintaining wireless networks, their capabilities make them popular tools for
malicious actors also . Hackers can use wireless sniffer software to steal data, spy on
network activity, and gather information to use in attacking the network. Logins (usernames
and passwords) are quite common targets for attackers using wireless sniffer tools.
Wireless network sniffing attacks usually target unsecure networks, like free WiFi publicly
places (coffee shops, hotels, airports, etc).Wireless sniffer tools also are commonly utilized
in “spoofing” attacks. Spoofing may be a sort of attack where a malicious party uses
information obtained by a wireless sniffer to impersonate another machine on the network.
Spoofing attacks often target business’ networks and may be wont to steal sensitive
information or run man-in-the-middle attacks against network hosts.There are two modes of
wireless sniffing: monitor mode and promiscuous mode. In monitor mode, a wireless sniffer
is in a position to gather and skim incoming data without sending any data of its own. A
wireless sniffing attack in monitor mode are often very difficult to detect due to this. In
promiscuous mode, a sniffer is in a position to read all data flowing into and out of a
wireless access point. Since a wireless sniffer in promiscuous mode also sniffs outgoing
data, the sniffer itself actually transmits data across the network. This makes wireless
sniffing attacks in promiscuous mode easier to detect. it’s more common for attackers to
use promiscuous mode in sniffing attacks because promiscuous mode allows attackers to
intercept the complete range of knowledge flowing through an access point.
Preventing Wireless Sniffer AttacksThere are several measures that organizations should
fancy mitigate wireless packet sniffer attacks. First off, organizations (and individual users)
should refrain from using insecure protocols. Commonly used insecure protocols include
basic HTTP authentication, File Transfer Protocol (FTP), and Telnet. Secure protocols like
HTTPS, Secure File Transfer Protocol (SFTP), and Secure Shell (SSH) should be utilized
in place of their insecure alternatives when possible. Secure protocols make sure that any
information transmitted will automatically be encrypted. If an insecure protocol must be
used, organizations themselves got to encrypt any data which will be sent using that
protocol. Virtual Private Networks (VPNs) are often wont to encrypt internet traffic and are a
well-liked tool for organizations today.Additionally to encrypting information and usingsecure protocols, companies can prevent attacks by using wireless sniffer software to smell
their own networks. this enables security teams to look at their networks from an attacker’s
perspective and find out sniffing vulnerabilities and attacks ongoing . While this method
won’t be effective in discovering wireless network sniffers in monitor mode, it’s possible to
detect sniffers in promiscuous mode (the preferred mode for attackers) by sniffing your own
network.
Tools for Detecting Packet SniffersWireless sniffer software programs frequently include
features like intrusion and hidden network detection for helping organizations discover
malicious sniffers on their networks. additionally to using features that are built into wireless
sniffer tools, there are many aftermarket tools available that are designed specifically for
detecting sniffing attacks. These tools typically perform functions like monitoring network
traffic or scanning network cards in promiscuous mode to detect wireless network sniffers.
There are dozens of options (both paid and open source) for sniffer detection tools, so
organizational security teams will got to do some research before selecting the proper tool
for his or her needs.