312-50v11 Practice Test

Something you have and something you know

Integrity and computational in-feasibility

Fuzzingautomated testing can be used to randomly generate invalid input in an attempt to crash

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

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