ECCouncil 312-50v11 - Certified Ethical Hacker Exam (CEH v11)

Buffer overflow this attack is an anomaly that happens when software writing data to a buffer overflows the buffer’s capacity, leading to adjacent memory locations being overwritten. In other words, an excessive amount of information is being passed into a container that doesn’t have enough space, which information finishes up replacing data in adjacent containers.Buffer overflows are often exploited by attackers with a goal of modifying a computer’s memory so as to undermine or take hold of program execution.

What’s a buffer?A buffer, or data buffer, is a neighborhood of physical memory storage wont to temporarily store data while it’s being moved from one place to a different . These buffers typically sleep in RAM memory. Computers frequently use buffers to assist improve performance; latest hard drives cash in of buffering to efficiently access data, and lots of online services also use buffers. for instance , buffers are frequently utilized in online video streaming to stop interruption. When a video is streamed, the video player downloads and stores perhaps 20% of the video at a time during a buffer then streams from that buffer. This way, minor drops in connection speed or quick service disruptions won’t affect the video stream performance.Buffers are designed to contain specific amounts of knowledge . Unless the program utilizing the buffer has built-in instructions to discard data when an excessive amount of is shipped to the buffer, the program will overwrite data in memory adjacent to the buffer.Buffer overflows are often exploited by attackers to corrupt software. Despite being well-understood, buffer overflow attacks are still a serious security problem that torment cyber-security teams. In 2014 a threat referred to as ‘heartbleed’ exposed many many users to attack due to a buffer overflow vulnerability in SSL software.

How do attackers exploit buffer overflows?An attacker can deliberately feed a carefully crafted input into a program which will cause the program to undertake and store that input during a buffer that isn’t large enough, overwriting portions of memory connected to the buffer space. If the memory layout of the program is well-defined, the attacker can deliberately overwrite areas known to contain executable code. The attacker can then replace this code together with his own executable code, which may drastically change how the program is meant to figure .For example if the overwritten part in memory contains a pointer (an object that points to a different place in memory) the attacker’s code could replace that code with another pointer that points to an exploit payload. this will transfer control of the entire program over to theattacker’s code.

https://www.mcafee.com/enterprise/en-us/security-awareness/ransomware/what-is-fileless-malware.html

One may append the comment “–” operator along with the String for the username and whole avoid executing the password segment of the SQL query. Everything when the — operator would be considered as comment and not dead.

To launch such an attack, the value passed for name could be ’OR ‘1’=‘1’ ; —Statement = “SELECT * FROM ‘CustomerDB’ WHERE ‘name’ = ‘ ”+ userName + “ ‘ AND ‘password’ = ‘ ” + passwd + “ ‘ ; ”

Statement = “SELECT * FROM ‘CustomerDB’ WHERE ‘name’ = ‘ ’ OR ‘1’=‘1‘;– + “ ‘ AND ‘password’ = ‘ ” + passwd + “ ‘ ; ”

All the records from the customer database would be listed.

Yet, another variation of the SQL Injection Attack can be conducted in dbms systems that allow multiple SQL injection statements. Here, we will also create use of the vulnerability in sure dbms whereby a user provided field isn’t strongly used in or isn’t checked for sort constraints.

This could take place once a numeric field is to be employed in a SQL statement; but, the programmer makes no checks to validate that the user supplied input is numeric.

Variation is an evasion technique whereby the attacker can easily evade any comparison statement. The attacker does this by placing characters such as “' or '1'='1'” in any basic injection statement such as “or 1=1” or with other accepted SQL comments.

Evasion Technique: Variation Variation is an evasion technique whereby the attacker can easily evade any comparison statement. The attacker does this by placing characters such as “' or '1'='1'” in any basic injection statement such as “or 1=1” or with other accepted SQL comments. The SQL interprets this as a comparison between two strings or characters instead of two numeric values. As the evaluation of two strings yields a true statement, similarly, the evaluation of two numeric values yields a true statement, thus rendering the evaluation of the complete query unaffected. It is also possible to write many other signatures; thus, there are infinite possibilities of variation as well. The main aim of the attacker is to have a WHERE statement that is always evaluated as “true” so that any mathematical or string comparison can be used, where the SQL can perform the same.

Triple DES is another mode of DES operation. It takes three 64-bit keys, for an overall key length of 192 bits. In Stealth, you merely type within the entire 192-bit (24 character) key instead of entering each of the three keys individually. The Triple DES DLL then breaks the user-provided key into three subkeys, padding the keys if necessary in order that they are each 64 bits long. The procedure for encryption is strictly an equivalent as regular DES, but it’s repeated 3 times , hence the name Triple DES. the info is encrypted with the primary key, decrypted with the second key, and eventually encrypted again with the third key.Triple DES runs 3 times slower than DES, but is far safer if used properly. The procedure for decrypting something is that the same because the procedure for encryption, except it’s executed in reverse. Like DES, data is encrypted and decrypted in 64-bit chunks. Although the input key for DES is 64 bits long, the particular key employed by DES is merely 56 bits long . the smallest amount significant (right-most) bit in each byte may be a parity , and will be set in order that there are always an odd number of 1s in every byte. These parity bits are ignored, so only the seven most vital bits of every byte are used, leading to a key length of 56 bits. this suggests that the effective key strength for Triple DES is really 168 bits because each of the three keys contains 8 parity bits that aren’t used during the encryption process.Triple DES ModesTriple ECB (Electronic Code Book)• This variant of Triple DES works precisely the same way because the ECB mode of DES.• this is often the foremost commonly used mode of operation.Triple CBC (Cipher Block Chaining)• This method is extremely almost like the quality DES CBC mode.• like Triple ECB, the effective key length is 168 bits and keys are utilized in an equivalent manner, as described above, but the chaining features of CBC mode also are employed.• the primary 64-bit key acts because the Initialization Vector to DES.• Triple ECB is then executed for one 64-bit block of plaintext.• The resulting ciphertext is then XORed with subsequent plaintext block to be encrypted, and therefore the procedure is repeated.• This method adds an additional layer of security to Triple DES and is therefore safer than Triple ECB, although it’s not used as widely as Triple ECB.

https://hub.packtpub.com/discovering-network-hosts-with-tcp-syn-and-tcp-ack-ping-scans-in-nmaptutorial/