CVE-2018-20185 - Out-of-bounds Read

Severity

26%

Complexity

49%

Confidentiality

48%

In GraphicsMagick 1.4 snapshot-20181209 Q8 on 32-bit platforms, there is a heap-based buffer over-read in the ReadBMPImage function of bmp.c, which allows attackers to cause a denial of service via a crafted bmp image file. This only affects GraphicsMagick installations with customized BMP limits.

In GraphicsMagick 1.4 snapshot-20181209 Q8 on 32-bit platforms, there is a heap-based buffer over-read in the ReadBMPImage function of bmp.c, which allows attackers to cause a denial of service via a crafted bmp image file. This only affects GraphicsMagick installations with customized BMP limits.

CVSS 3.0 Base Score 5.3. CVSS Attack Vector: network. CVSS Attack Complexity: high. CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H).

CVSS 2.0 Base Score 2.6. CVSS Attack Vector: network. CVSS Attack Complexity: high. CVSS Vector: (AV:N/AC:H/Au:N/C:N/I:N/A:P).

Demo Examples

Out-of-bounds Read

CWE-125

In the following code, the method retrieves a value from an array at a specific array index location that is given as an input parameter to the method


               
}
return value;// check that the array index is less than the maximum// length of the array
value = array[index];// get the value at the specified index of the array
// if array index is invalid then output error message// and return value indicating error
value = -1;

However, this method only verifies that the given array index is less than the maximum length of the array but does not check for the minimum value (CWE-839). This will allow a negative value to be accepted as the input array index, which will result in a out of bounds read (CWE-125) and may allow access to sensitive memory. The input array index should be checked to verify that is within the maximum and minimum range required for the array (CWE-129). In this example the if statement should be modified to include a minimum range check, as shown below.


               
...// check that the array index is within the correct// range of values for the array

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