CVE-2009-4537 - Improper Input Validation

Severity

78%

Complexity

99%

Confidentiality

115%

drivers/net/r8169.c in the r8169 driver in the Linux kernel 2.6.32.3 and earlier does not properly check the size of an Ethernet frame that exceeds the MTU, which allows remote attackers to (1) cause a denial of service (temporary network outage) via a packet with a crafted size, in conjunction with certain packets containing A characters and certain packets containing E characters; or (2) cause a denial of service (system crash) via a packet with a crafted size, in conjunction with certain packets containing '\0' characters, related to the value of the status register and erroneous behavior associated with the RxMaxSize register. NOTE: this vulnerability exists because of an incorrect fix for CVE-2009-1389.

drivers/net/r8169.c in the r8169 driver in the Linux kernel 2.6.32.3 and earlier does not properly check the size of an Ethernet frame that exceeds the MTU, which allows remote attackers to (1) cause a denial of service (temporary network outage) via a packet with a crafted size, in conjunction with certain packets containing A characters and certain packets containing E characters; or (2) cause a denial of service (system crash) via a packet with a crafted size, in conjunction with certain packets containing '\0' characters, related to the value of the status register and erroneous behavior associated with the RxMaxSize register. NOTE: this vulnerability exists because of an incorrect fix for CVE-2009-1389.

CVSS 2.0 Base Score 7.8. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (AV:N/AC:L/Au:N/C:N/I:N/A:C).

Demo Examples

Improper Input Validation

CWE-20

This example demonstrates a shopping interaction in which the user is free to specify the quantity of items to be purchased and a total is calculated.


               
...

The user has no control over the price variable, however the code does not prevent a negative value from being specified for quantity. If an attacker were to provide a negative value, then the user would have their account credited instead of debited.

Improper Input Validation

CWE-20

This example asks the user for a height and width of an m X n game board with a maximum dimension of 100 squares.


               
.../* board dimensions */
die("No integer passed: Die evil hacker!\n");
die("No integer passed: Die evil hacker!\n");
die("Value too large: Die evil hacker!\n");

While this code checks to make sure the user cannot specify large, positive integers and consume too much memory, it does not check for negative values supplied by the user. As a result, an attacker can perform a resource consumption (CWE-400) attack against this program by specifying two, large negative values that will not overflow, resulting in a very large memory allocation (CWE-789) and possibly a system crash. Alternatively, an attacker can provide very large negative values which will cause an integer overflow (CWE-190) and unexpected behavior will follow depending on how the values are treated in the remainder of the program.

Improper Input Validation

CWE-20

The following example shows a PHP application in which the programmer attempts to display a user's birthday and homepage.


               
echo "Birthday: $birthday<br>Homepage: <a href=$homepage>click here</a>"

The programmer intended for $birthday to be in a date format and $homepage to be a valid URL. However, since the values are derived from an HTTP request, if an attacker can trick a victim into clicking a crafted URL with <script> tags providing the values for birthday and / or homepage, then the script will run on the client's browser when the web server echoes the content. Notice that even if the programmer were to defend the $birthday variable by restricting input to integers and dashes, it would still be possible for an attacker to provide a string of the form:


               
2009-01-09--

If this data were used in a SQL statement, it would treat the remainder of the statement as a comment. The comment could disable other security-related logic in the statement. In this case, encoding combined with input validation would be a more useful protection mechanism.

Furthermore, an XSS (CWE-79) attack or SQL injection (CWE-89) are just a few of the potential consequences when input validation is not used. Depending on the context of the code, CRLF Injection (CWE-93), Argument Injection (CWE-88), or Command Injection (CWE-77) may also be possible.

Improper Input Validation

CWE-20

This function attempts to extract a pair of numbers from a user-supplied string.


               
}
die("Did not specify integer value. Die evil hacker!\n");
/* proceed assuming n and m are initialized correctly */

This code attempts to extract two integer values out of a formatted, user-supplied input. However, if an attacker were to provide an input of the form:


               
123:

then only the m variable will be initialized. Subsequent use of n may result in the use of an uninitialized variable (CWE-457).

Improper Input Validation

CWE-20

The following example takes a user-supplied value to allocate an array of objects and then operates on the array.


               
}
list[0] = new Widget();
die("Negative value supplied for list size, die evil hacker!");

This example attempts to build a list from a user-specified value, and even checks to ensure a non-negative value is supplied. If, however, a 0 value is provided, the code will build an array of size 0 and then try to store a new Widget in the first location, causing an exception to be thrown.

Improper Input Validation

CWE-20

This application has registered to handle a URL when sent an intent:


               
}......
}
}
int length = URL.length();
...

The application assumes the URL will always be included in the intent. When the URL is not present, the call to getStringExtra() will return null, thus causing a null pointer exception when length() is called.

Overview

Type

Linux

First reported 15 years ago

2010-01-12 17:30:00

Last updated 6 years ago

2018-11-16 15:52:00

Affected Software

Linux Kernel

Debian GNU/Linux 5.0

5.0

References

http://blog.c22.cc/2009/12/27/26c3-cat-procsysnetipv4fuckups/

Third Party Advisory

http://events.ccc.de/congress/2009/Fahrplan/events/3596.en.html

Third Party Advisory

FEDORA-2010-1787

Mailing List, Third Party Advisory

SUSE-SA:2010:031

Mailing List, Third Party Advisory

[linux-netdev] 20091228 [PATCH RFC] r8169: straighten out overlength frame detection

Mailing List, Third Party Advisory

http://marc.info/?t=126202986900002&r=1&w=2

Mailing List, Third Party Advisory

38031

Third Party Advisory

38610

Third Party Advisory

39742

Third Party Advisory

39830

Third Party Advisory

40645

Third Party Advisory

1023419

Third Party Advisory, VDB Entry

http://twitter.com/dakami/statuses/7104238406

Third Party Advisory

DSA-2053

Third Party Advisory

SUSE-SA:2010:023

Third Party Advisory

[oss-security] 20091228 CVE requests - kernel security regressions for CVE-2009-1385/and -1389

Mailing List, Third Party Advisory

[oss-security] 20091229 Re: CVE requests - kernel security regressions for CVE-2009-1385/and -1389

Mailing List, Third Party Advisory

[oss-security] 20091231 Re: CVE requests - kernel security regressions for CVE-2009-1385/and -1389

Mailing List, Third Party Advisory

RHSA-2010:0019

Third Party Advisory

RHSA-2010:0020

Third Party Advisory

RHSA-2010:0041

Third Party Advisory

RHSA-2010:0053

Third Party Advisory

RHSA-2010:0111

Third Party Advisory

37521

Third Party Advisory, VDB Entry

ADV-2010-1857

Third Party Advisory

https://bugzilla.redhat.com/show_bug.cgi?id=550907

Issue Tracking, Third Party Advisory

kernel-r8169-dos(55647)

Third Party Advisory, VDB Entry

oval:org.mitre.oval:def:7443

Third Party Advisory

oval:org.mitre.oval:def:9439

Third Party Advisory

RHSA-2010:0095

Third Party Advisory

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