Weakness (CWE)
CWE-120: Buffer Copy without Checking Size of Input
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
How to prevent it (8 mitigations)
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Requirements
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer.
Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
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Architecture and Design
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Examples include the Safe C String Library (SafeStr) by Messier and Viega [REF-57], and the Strsafe.h library from Microsoft [REF-56]. These libraries provide safer versions of overflow-prone string-handling functions.
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Operation, Build and Compilation
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.
D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
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Implementation
Consider adhering to the following rules when allocating and managing an application's memory:
- Double check that your buffer is as large as you specify.
- When using functions that accept a number of bytes to copy, such as strncpy(), be aware that if the destination buffer size is equal to the source buffer size, it may not NULL-terminate the string.
- Check buffer boundaries if accessing the buffer in a loop and make sure there is no danger of writing past the allocated space.
- If necessary, truncate all input strings to a reasonable length before passing them to the copy and concatenation functions.
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Implementation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
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Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
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Operation, Build and Compilation
Run or compile the software using features or extensions that randomly arrange the positions of a program's executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.
Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as "rebasing" (for Windows) and "prelinking" (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.
For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].
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Operation
Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX [REF-60] [REF-61]. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment.
For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].
Source: MITRE CWE-120
3,303 results · Feed
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High 8.8
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A vulnerability was found in D-Link DIR-605L 2.13B01 BETA. It has been declared as critical. This vulnerability affects the function formSetDomainFilter of the file /goform/formSetDomainFilter. The manipulation of the argument curTime leads to buffer overflow…
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High 8.0
The CGI endpoints v2x00.cgi and cgiwcg.cgi of DrayTek Vigor3910 devices through 4.3.2.6 are vulnerable to buffer overfl…
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High 8.0
Buffer Overflow vulnerabilities exist in DrayTek Vigor310 devices through 4.3.2.6 (in the Vigor management UI) because …
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Medium 4.4
Buffer copy without checking size of input ('Classic Buffer Overflow') vulnerability in backup task management function…
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Medium 4.4
Buffer copy without checking size of input ('Classic Buffer Overflow') vulnerability in connection management functiona…
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High 8.2
Buffer copy without checking size of input ('Classic Buffer Overflow') vulnerability in vss service component in Synolo…
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Medium 6.8
Sony XAV-AX5500 USB Configuration Descriptor Buffer Overflow Remote Code Execution Vulnerability
Sony XAV-AX5500 USB Configuration Descriptor Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows physically present attackers to execute arbitrary code on affected installations of Sony XAV-AX5500 devices. Authentication is not requ…
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Medium 6.3
SourceCodester Telecom Billing Management System login buffer overflow
A vulnerability has been found in SourceCodester Telecom Billing Management System 1.0 and classified as critical. This vulnerability affects the function login. The manipulation of the argument uname leads to buffer overflow. The exploit has been disclosed t…
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Critical 9.8
Tenda AC8v4 V16.03.34.06 has a stack overflow vulnerability in the fromAdvSetMacMtuWan function.
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High 8.2
Triangle Microworks TMW IEC 61850 Client source code libraries before 12.2.0 lack a buffer size check when processing r…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sProfileName parameter at fextobj.cgi. T…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sProfileName parameter at v2x00.cgi. Thi…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sIpv6AiccuUser parameter at inetipv6.cgi…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the AControlIp1 parameter at acontrol.cgi. T…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sBPA_Pwd parameter at inet15.cgi. This v…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sPubKey parameter at dialin.cgi. This vu…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sProfileName parameter at usergrp.cgi. T…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the pub_key parameter at v2x00.cgi. This vul…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the profname parameter at v2x00.cgi. This vu…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the ipaddrmsk%d parameter at v2x00.cgi. This…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the iprofileidx parameter at dialin.cgi. Thi…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the iProfileIdx parameter at v2x00.cgi. This…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sStRtMskShow parameter at ipstrt.cgi. Th…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the trapcomm parameter at cgiswm.cgi. This v…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the saveitem parameter at lan2lan.cgi. This …
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sAppName parameter at sslapp.cgi. This v…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sSrvName parameter at service.cgi. This …
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sPPPSrvNm parameter at fwuser.cgi. This …
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the ssidencrypt%d parameter at v2x00.cgi. Th…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the extRadSrv2 parameter at cgiapp.cgi. This…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sBPA_UsrNme parameter at inet15.cgi. Thi…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sInRCSecret0 parameter at v2x00.cgi. Thi…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the newProname parameter at v2x00.cgi. This …
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the fid parameter at v2x00.cgi. This vulnera…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the saveVPNProfile parameter at v2x00.cgi. T…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sProfName parameter at v2x00.cgi. This v…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sProfileName parameter at wizfw.cgi. Thi…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the sDnsPro parameter at v2x00.cgi. This vul…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the pb parameter at v2x00.cgi. This vulnerab…
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High 7.5
Draytek Vigor 3910 v4.3.2.6 was discovered to contain a buffer overflow in the queryret parameter at v2x00.cgi. This vu…