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Improper Restriction of Operations within the Bounds of a Memory Buffer

CVE-2018-14779

Medium
6.8/10

Summary

A buffer overflow issue was discovered in the Yubico-Piv 1.5.0 smartcard driver. The file lib/ykpiv.c contains the following code in the function `ykpiv_transfer_data()`: {% highlight c %} if(*out_len + recv_len - 2 > max_out) { fprintf(stderr, "Output buffer to small, wanted to write %lu, max was %lu.", *out_len + recv_len - 2, max_out); } if(out_data) { memcpy(out_data, data, recv_len - 2); out_data += recv_len - 2; *out_len += recv_len - 2; } {% endhighlight %} -- it is clearly checked whether the buffer is big enough to hold the data copied using `memcpy()`, but no error handling happens to avoid the `memcpy()` in such cases. This code path can be triggered with malicious data coming from a smartcard.

  • LOW
  • PHYSICAL
  • HIGH
  • UNCHANGED
  • NONE
  • NONE
  • HIGH
  • HIGH

CWE-119 - Buffer Overflow

Buffer overflow attacks involve data transit and operations exceeding the restricted memory buffer, thereby corrupting or overwriting data in adjacent memory locations. Such overflow allows the attacker to run arbitrary code or manipulate the existing code to cause privilege escalation, data breach, denial of service, system crash and even complete system compromise. Given that languages such as C and C++ lack default safeguards against overwriting or accessing data in their memory, applications utilizing these languages are most susceptible to buffer overflows attacks.

References

Advisory Timeline

  • Published