understanding the dangers of sprintf(…)

Question

OWASP says:

\"C library functions such as strcpy (), strcat (), sprintf () and vsprintf () operate on null terminated strings and perform no bou

Answer 1

The sprintf function, when used with certain format specifiers, poses two types of security risk: (1) writing memory it shouldn't; (2) reading memory it shouldn't. If snprintf is used with a size parameter that matches the buffer, it won't write anything it shouldn't. Depending upon the parameters, it may still read stuff it shouldn't. Depending upon the operating environment and what else a program is doing, the danger from improper reads may or may not be less severe than that from improper writes.