CWE-126: Buffer Over-read
The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.
How it's found
Buffer Over-read is a specific, narrowly defined instance of a broader pattern. Testers confirm it with targeted code review and a proof-of-concept input that exercises the exact code path this weakness describes.
Vulnerable vs. safe
/* Validate number of parameters and ensure valid content */
/* copy filename parameter to variable, may cause off-by-one overflow */
/* copy pattern parameter to variable, may cause off-by-one overflow */char Filename[256];char Pattern[32];...strncpy(Filename, argv[1], sizeof(Filename));strncpy(Pattern, argv[2], sizeof(Pattern));printf("Searching file: %s for the pattern: %s\n", Filename, Pattern);Scan_File(Filename, Pattern);int main(int argc, char **argv){}/* copy filename parameter to variable, no off-by-one overflow */
/* copy pattern parameter to variable, no off-by-one overflow */
strncpy(Filename, argv[2], sizeof(Filename)-1);Filename[255]='\0';strncpy(Pattern, argv[3], sizeof(Pattern)-1);
Pattern[31]='\0';Consequences
- Read Memory
- Bypass Protection Mechanism: By reading out-of-bounds memory, an attacker might be able to get secret values, such as memory addresses, which can bypass protection mechanisms such as ASLR in order to improve the reliability and likelihood of exploiting a separate weakness to achieve code execution instead of just denial of service.
- DoS: Crash, Exit, or Restart: An attacker might be able to cause a crash or other denial of service by causing the product to read a memory location that is not allowed (such as a segmentation fault), or to cause other conditions in which the read operation returns more data than is expected.
Where this fits in a TurboPentest engagement
TurboPentest's agentic pentest is powerful and covers a broad range of issues automatically. This particular class is best confirmed in a manual IntegSec engagement, where human pentesters apply deeper methodology and a larger context window than any automated pass.
Frequently asked questions
What is CWE-126?
The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.
How do you find Buffer Over-read?
Buffer Over-read is a specific, narrowly defined instance of a broader pattern. Testers confirm it with targeted code review and a proof-of-concept input that exercises the exact code path this weakness describes.
What is the impact of CWE-126?
Read Memory Bypass Protection Mechanism: By reading out-of-bounds memory, an attacker might be able to get secret values, such as memory addresses, which can bypass protection mechanisms such as ASLR in order to improve the reliability and likelihood of exploiting a separate weakness to achieve code execution instead of just denial of service. DoS: Crash, Exit, or Restart: An attacker might be able to cause a crash or other denial of service by causing the product to read a memory location that is not allowed (such as a segmentation fault), or to cause other conditions in which the read operation returns more data than is expected.
Does TurboPentest test for Buffer Over-read?
TurboPentest's agentic pentest is powerful and covers a broad range of issues automatically. This particular class is best confirmed in a manual IntegSec engagement, where human pentesters apply deeper methodology and a larger context window than any automated pass.
Related CWEs
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