Page History

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Compliant Solution (Windows)

The CryptGenRandomThe BCryptGenRandom() function  function does not run the risk of not being properly seeded because its arguments serve as seeders:

#include <stdio.h>
#include <Windows.h>
#include <Bcrypt.h>
#include <wincrypt<Ntstatus.h>
#include <stdio<Wincrypt.h>
 
void func(void) {
  HCRYPTPROV hCryptProvBCRYPT_ALG_HANDLE hAlgorithm = NULL;
  long rand_buf;
  /*PUCHAR ExamplepbBuffer of instantiating the CSP */
  if (CryptAcquireContext(&hCryptProv, NULL, NULL,= (PUCHAR) &rand_buf;
  ULONG cbBuffer                       PROV_RSA_FULL, 0)) {= sizeof(rand_buf);
  ULONG dwFlags printf("CryptAcquireContext succeeded.\n")= BCRYPT_USE_SYSTEM_PREFERRED_RNG;
  } else {
    printf("Error during CryptAcquireContext!\n")NTSTATUS status;
  }

  for (unsigned int i = 0; i < 10; ++i) {
    ifstatus = BCryptGenRandom(!CryptGenRandom(hCryptProvhAlgorithm, sizeof(rand_buf),
  pbBuffer, cbBuffer, dwFlags);
    if (status                 (BYTE *)&rand_buf)== STATUS_SUCCESS) {
      printf("Error\n"%ld, ", rand_buf);
    } else {
       printf("%ld, ", rand_buf);/* Handle Error */
    }
  }
}

The output is as follows:

1st run: -1597837311683378946, 9061306821957231690, -13080318861933176011, 1048837407-1745403355, -931041900883473417, -658114613882992405, -1709220953169629816, -10196972891824800038, 1802206541899851668,
         406505841,1702784647, 
2nd run: 885904119-58750553, -6873795561921870721, -17822968541973269161, 14437019161512649964, -624291047673518452, 2049692692234003619, -9904515631622633366, 1312389688, -1423078042125631172, 12570792112067680022,
         897185104,
3rd run: 190598304-189899579, -15374094641220698973, 1594174739752205360, -4244019161826365616, -197515347479310867, 8269129271430950090, 1705549595-283206168, -1515331215941773185, 474951399129633665,
         1982500583, 543448789, 

Risk Assessment

Automated Detection

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this rule on the CERT website.

Related Guidelines

Key here (explains table format and definitions)

CERT-CWE Mapping Notes

Key here for mapping notes

CWE

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-327 and MSC32-C

• Intersection( MSC30-C, MSC32-C) = Ø

• MSC32-C says to properly seed pseudorandom number generators. For example, if you call rand(), make sure to seed it properly by calling srand() first. So far, we haven’t found any calls to rand().

• Failure to seed a PRNG causes it to produce reproducible (hence insecure) series of random numbers.

• CWE-327 = Union( MSC32-C, list) where list =

• Invocation of broken/risky crypto algorithms that are not properly seeded

CWE-330 and MSC32-C

Independent( MSC30-C, MSC32-C, CON33-C)

CWE-330 = Union( MSC30-C, MSC32-C, CON33-C, list) where list = other improper use or creation of random values. (EG the would qualify)

MSC30-C, MSC32-C and CON33-C are independent, they have no intersections. They each specify distinct errors regarding PRNGs.

Bibliography

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