CVE-2024-43626 - Heap-based Buffer Overflow

Severity

78%

Complexity

18%

Confidentiality

98%

Windows Telephony Service Elevation of Privilege Vulnerability

CVSS 3.1 Base Score 7.8. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Demo Examples

Heap-based Buffer Overflow

CWE-122

While buffer overflow examples can be rather complex, it is possible to have very simple, yet still exploitable, heap-based buffer overflows:


               
}
strcpy(buf, argv[1]);

The buffer is allocated heap memory with a fixed size, but there is no guarantee the string in argv[1] will not exceed this size and cause an overflow.

Heap-based Buffer Overflow

CWE-122

This example applies an encoding procedure to an input string and stores it into a buffer.


               
}
return dst_buf;
die("user string too long, die evil hacker!");
else dst_buf[dst_index++] = user_supplied_string[i];
dst_buf[dst_index++] = ';';
/* encode to < */

The programmer attempts to encode the ampersand character in the user-controlled string, however the length of the string is validated before the encoding procedure is applied. Furthermore, the programmer assumes encoding expansion will only expand a given character by a factor of 4, while the encoding of the ampersand expands by 5. As a result, when the encoding procedure expands the string it is possible to overflow the destination buffer if the attacker provides a string of many ampersands.

Overview

Type

Microsoft Windows Server

First reported 1 week ago

2024-11-12 18:15:00

Last updated 2 days ago

2024-11-19 03:05:00

Affected Software

Microsoft Windows Server 2012

Microsoft Windows Server 2019

Microsoft Windows Server 2016

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