CVE-2019-0689 - Integer Overflow or Wraparound

Severity

46%

Complexity

39%

Confidentiality

106%

An elevation of privilege vulnerability exists due to an integer overflow in Windows Subsystem for Linux, aka 'Windows Subsystem for Linux Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2019-0682, CVE-2019-0692, CVE-2019-0693, CVE-2019-0694.

An elevation of privilege vulnerability exists due to an integer overflow in Windows Subsystem for Linux, aka 'Windows Subsystem for Linux Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2019-0682, CVE-2019-0692, CVE-2019-0693, CVE-2019-0694.

CVSS 3.0 Base Score 7.8. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

CVSS 2.0 Base Score 4.6. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (AV:L/AC:L/Au:N/C:P/I:P/A:P).

Demo Examples

Integer Overflow or Wraparound

CWE-190

The following image processing code allocates a table for images.


               
...

This code intends to allocate a table of size num_imgs, however as num_imgs grows large, the calculation determining the size of the list will eventually overflow (CWE-190). This will result in a very small list to be allocated instead. If the subsequent code operates on the list as if it were num_imgs long, it may result in many types of out-of-bounds problems (CWE-119).

Integer Overflow or Wraparound

CWE-190

The following code excerpt from OpenSSH 3.3 demonstrates a classic case of integer overflow:


               
}
for (i = 0; i < nresp; i++) response[i] = packet_get_string(NULL);

If nresp has the value 1073741824 and sizeof(char*) has its typical value of 4, then the result of the operation nresp*sizeof(char*) overflows, and the argument to xmalloc() will be 0. Most malloc() implementations will happily allocate a 0-byte buffer, causing the subsequent loop iterations to overflow the heap buffer response.

Integer Overflow or Wraparound

CWE-190

Integer overflows can be complicated and difficult to detect. The following example is an attempt to show how an integer overflow may lead to undefined looping behavior:


               
}
bytesRec += getFromInput(buf+bytesRec);

In the above case, it is entirely possible that bytesRec may overflow, continuously creating a lower number than MAXGET and also overwriting the first MAXGET-1 bytes of buf.

Integer Overflow or Wraparound

CWE-190

In this example the method determineFirstQuarterRevenue is used to determine the first quarter revenue for an accounting/business application. The method retrieves the monthly sales totals for the first three months of the year, calculates the first quarter sales totals from the monthly sales totals, calculates the first quarter revenue based on the first quarter sales, and finally saves the first quarter revenue results to the database.


               
}
return 0;// Variable for sales revenue for the quarter// Calculate quarterly total// Calculate the total revenue for the quarter

However, in this example the primitive type short int is used for both the monthly and the quarterly sales variables. In C the short int primitive type has a maximum value of 32768. This creates a potential integer overflow if the value for the three monthly sales adds up to more than the maximum value for the short int primitive type. An integer overflow can lead to data corruption, unexpected behavior, infinite loops and system crashes. To correct the situation the appropriate primitive type should be used, as in the example below, and/or provide some validation mechanism to ensure that the maximum value for the primitive type is not exceeded.


               
}
...// Calculate quarterly total// Calculate the total revenue for the quarter

Note that an integer overflow could also occur if the quarterSold variable has a primitive type long but the method calculateRevenueForQuarter has a parameter of type short.

Overview

Type

Microsoft Windows

First reported 5 years ago

2019-04-09 00:29:00

Last updated 5 years ago

2019-04-09 17:08:00

Affected Software

Microsoft Windows 10 1709

1709

Microsoft Windows 10 1803

1803

Microsoft Windows 10 1809

1809

Microsoft Windows Server 2016 1709

1709

Microsoft Windows Server 2016 1803

1803

Microsoft Windows Server 2019

Stay updated

ExploitPedia is constantly evolving. Sign up to receive a notification when we release additional functionality.

Get in touch

If you'd like to report a bug or have any suggestions for improvements then please do get in touch with us using this form. We will get back to you as soon as we can.