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Heap Overflow
A heap overflow, heap overrun, or heap smashing is a type of buffer overflow that occurs in the heap data area. Heap overflows are exploitable in a different manner to that of stack-based overflows. Memory on the heap is dynamically allocated at runtime and typically contains program data. Exploitation is performed by corrupting this data in specific ways to cause the application to overwrite internal structures such as linked list pointers. The canonical heap overflow technique overwrites dynamic memory allocation linkage (such as malloc metadata) and uses the resulting pointer exchange to overwrite a program function pointer. For example, on older versions of Linux, two buffers allocated next to each other on the heap could result in the first buffer overwriting the second buffer's metadata. By setting the in-use bit to zero of the second buffer and setting the length to a small negative value which allows null bytes to be copied, when the program calls free() on the first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NX Bit
The NX bit (no-execute bit) is a processor feature that separates areas of a virtual address space (the memory layout a program uses) into sections for storing data or program instructions. An operating system supporting the NX bit can mark certain areas of the virtual address space as non-executable, preventing the processor from running any code stored there. This technique, known as executable space protection or Write XOR Execute, protects computers from malicious software that attempts to insert harmful code into another program’s data storage area and execute it, such as in a buffer overflow attack. The term "NX bit" was introduced by Advanced Micro Devices (AMD) as a marketing term. Intel markets this feature as the XD bit (execute disable), while the MIPS architecture refers to it as the XI bit (execute inhibit). In the ARM architecture, introduced in ARMv6, it is known as XN (execute never). The term NX bit is often used broadly to describe similar executable space p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exploit (computer Security)
An exploit is a method or piece of code that takes advantage of Vulnerability (computer security), vulnerabilities in software, Application software, applications, Computer network, networks, operating systems, or Computer hardware, hardware, typically for malicious purposes. The term "exploit" derives from the English verb "to exploit," meaning "to use something to one’s own advantage." Exploits are designed to identify flaws, bypass security measures, gain unauthorized access to systems, take control of systems, install malware, or data breach, steal sensitive data. While an exploit by itself may not be a malware, it serves as a vehicle for delivering malicious software by breaching security controls. Researchers estimate that malicious exploits cost the global economy over US$450 billion annually. In response to this threat, organizations are increasingly utilizing cyber threat intelligence to identify vulnerabilities and prevent hacks before they occur. Description Expl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stack Buffer Overflow
In software, a stack buffer overflow or stack buffer overrun occurs when a program writes to a memory address on the program's call stack outside of the intended data structure, which is usually a fixed-length buffer. Stack buffer overflow bugs are caused when a program writes more data to a buffer located on the stack than what is actually allocated for that buffer. This almost always results in corruption of adjacent data on the stack, and in cases where the overflow was triggered by mistake, will often cause the program to crash or operate incorrectly. Stack buffer overflow is a type of the more general programming malfunction known as buffer overflow (or buffer overrun). Overfilling a buffer on the stack is more likely to derail program execution than overfilling a buffer on the heap because the stack contains the return addresses for all active function calls. A stack buffer overflow can be caused deliberately as part of an attack known as . If the affected program is runni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heap Spraying
In computer security, heap spraying is a technique used in exploits to facilitate arbitrary code execution. The part of the source code of an exploit that implements this technique is called a heap spray. In general, code that ''sprays the heap'' attempts to put a certain sequence of bytes at a predetermined location in the memory of a target process by having it allocate (large) blocks on the process's heap and fill the bytes in these blocks with the right values. Operation A heap spray does not actually exploit any security issues but it can be used to make a vulnerability easier to exploit. A heap spray by itself cannot be used to break any security boundaries: a separate security issue is needed. Exploiting security issues is often hard because various factors can influence this process. Chance alignments of memory and timing introduce a lot of randomness (from the attacker's point of view). A heap spray can be used to introduce a large amount of order to compensate for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base Address
In computing, a base address is an address serving as a reference point ("base") for other addresses. Related addresses can be accessed using an ''addressing scheme''. Under the ''relative addressing'' scheme, to obtain an absolute address, the relevant base address is taken and an offset (aka displacement) is added to it. Under this type of scheme, the base address is the lowest numbered address within a prescribed range, to facilitate adding related positive-valued offsets. In IBM System/360 architecture, the base address is a 24-bit value in a general register (extended in steps to 64 bits in z/Architecture), and the offset is a 12 bit value in the instruction (extended to 20 bits in z/Architecture). See also * Index register An index register in a computer's central processing unit, CPU is a processor register (or an assigned memory location) used for pointing to operand addresses during the run of a program. It is useful for stepping through String (computer scienc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows 7
Windows 7 is a major release of the Windows NT operating system developed by Microsoft. It was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on July 22, 2009, and became generally available on October 22, 2009. It is the successor to Windows Vista, released nearly three years earlier. Windows 7's Windows Server, server counterpart, Windows Server 2008 R2, was released at the same time. It sold over 630 million copies before it was succeeded by Windows 8 in October 2012. Extended support ended on January 14, 2020, over 10 years after the release of Windows 7, and the operating system ceased receiving further updates. A paid support program was available for enterprises, providing security updates for Windows 7 for up to three years since the official end of life. Windows 7 was intended to be an incremental upgrade to Windows Vista, addressing the previous OS's poor reception while maintaining hardware and software compatibility as well as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows Vista
Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, released five years earlier, which was then the longest time span between successive releases of Microsoft Windows. It was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on November 8, 2006, and over the following two months, it was released in stages to business customers, original equipment manufacturers (OEMs), and retail channels. On January 30, 2007, it was released internationally and was made available for purchase and download from the Windows Marketplace; it is the first release of Windows to be made available through a digital distribution platform. Development of Windows Vista began in 2001 under the codename "Longhorn"; originally envisioned as a minor successor to Windows XP, it feature creep, gradually included numerous new features from the then-next major release of Windows codenamed "Blackc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows XP
Windows XP is a major release of Microsoft's Windows NT operating system. It was released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct successor to Windows 2000 for high-end and business users and Windows Me for home users. Development of Windows XP began in the late 1990s under the codename "Windows Neptune, Neptune", built on the Architecture of Windows NT#Kernel, Windows NT kernel and explicitly intended for mainstream consumer use. An updated version of Windows 2000 was also initially planned for the business market. However, in January 2000, both projects were scrapped in favor of a single OS codenamed "Whistler", which would serve as a single platform for both consumer and business markets. As a result, Windows XP is the first consumer edition of Windows not based on the Windows 95 kernel or MS-DOS. Upon its release, Windows XP received critical acclaim, noting increased performance and stability (especially compared to Wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows Server 2003
Windows Server 2003, codenamed "Whistler Server", is the sixth major version of the Windows NT operating system produced by Microsoft and the first server version to be released under the Windows Server brand name. It is part of the Windows NT family of operating systems and was released to manufacturing on March 28, 2003 and generally available on April 24, 2003. Windows Server 2003 is the successor to Windows 2000#Editions, the Server editions of Windows 2000 and the predecessor to Windows Server 2008. An updated version, Windows Server 2003 R2, was released to manufacturing on December 6, 2005. Windows Server 2003 is based on Windows XP. Its kernel has also been used in Windows XP editions#Windows XP 64-Bit Edition, Windows XP 64-bit Edition and Windows XP Professional x64 Edition. It is the final version of Windows Server that supports processors without ACPI. As of July 2016, 18% of organizations used servers that were running Windows Server 2003. Overview Windows Serve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASLR
Address space layout randomization (ASLR) is a computer security technique involved in preventing exploitation of memory corruption vulnerabilities. In order to prevent an attacker from reliably redirecting code execution to, for example, a particular exploited function in memory, ASLR randomly arranges the address space positions of key data areas of a process, including the base of the executable and the positions of the stack, heap and libraries. When applied to the kernel, this technique is called ''kernel address space layout randomization'' (''KASLR''). History The Linux PaX project first coined the term "ASLR", and published the first design and implementation of ASLR in July 2001 as a patch for the Linux kernel. It is seen as a complete implementation, providing a patch for kernel stack randomization since October 2002. The first mainstream operating system to support ASLR by default was OpenBSD version 3.4 in 2003, followed by Linux in 2005. Benefits Address ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
