CVE-2007-3999 - Improper Restriction of Operations within the Bounds of a Memory Buffer

Severity

99%

Complexity

99%

Confidentiality

165%

Stack-based buffer overflow in the svcauth_gss_validate function in lib/rpc/svc_auth_gss.c in the RPCSEC_GSS RPC library (librpcsecgss) in MIT Kerberos 5 (krb5) 1.4 through 1.6.2, as used by the Kerberos administration daemon (kadmind) and some third-party applications that use krb5, allows remote attackers to cause a denial of service (daemon crash) and probably execute arbitrary code via a long string in an RPC message.

Stack-based buffer overflow in the svcauth_gss_validate function in lib/rpc/svc_auth_gss.c in the RPCSEC_GSS RPC library (librpcsecgss) in MIT Kerberos 5 (krb5) 1.4 through 1.6.2, as used by the Kerberos administration daemon (kadmind) and some third-party applications that use krb5, allows remote attackers to cause a denial of service (daemon crash) and probably execute arbitrary code via a long string in an RPC message.

CVSS 2.0 Base Score 9.9. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (AV:N/AC:L/Au:N/C:C/I:C/A:C).

Demo Examples

Improper Restriction of Operations within the Bounds of a Memory Buffer

CWE-119

This example takes an IP address from a user, verifies that it is well formed and then looks up the hostname and copies it into a buffer.


               
}
strcpy(hostname, hp->h_name);/*routine that ensures user_supplied_addr is in the right format for conversion */

This function allocates a buffer of 64 bytes to store the hostname, however there is no guarantee that the hostname will not be larger than 64 bytes. If an attacker specifies an address which resolves to a very large hostname, then we may overwrite sensitive data or even relinquish control flow to the attacker.

Note that this example also contains an unchecked return value (CWE-252) that can lead to a NULL pointer dereference (CWE-476).

Improper Restriction of Operations within the Bounds of a Memory Buffer

CWE-119

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.

Improper Restriction of Operations within the Bounds of a Memory Buffer

CWE-119

The following example asks a user for an offset into an array to select an item.


               
}
printf("You selected %s\n", items[index-1]);

The programmer allows the user to specify which element in the list to select, however an attacker can provide an out-of-bounds offset, resulting in a buffer over-read (CWE-126).

Improper Restriction of Operations within the Bounds of a Memory Buffer

CWE-119

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

Improper Restriction of Operations within the Bounds of a Memory Buffer

CWE-119

Windows provides the _mbs family of functions to perform various operations on multibyte strings. When these functions are passed a malformed multibyte string, such as a string containing a valid leading byte followed by a single null byte, they can read or write past the end of the string buffer causing a buffer overflow. The following functions all pose a risk of buffer overflow: _mbsinc _mbsdec _mbsncat _mbsncpy _mbsnextc _mbsnset _mbsrev _mbsset _mbsstr _mbstok _mbccpy _mbslen

Overview

Type

Mit Kerberos 5

First reported 17 years ago

2007-09-05 10:17:00

Last updated 5 years ago

2020-01-21 15:45:00

Affected Software

Mit Kerberos 5 1.4

1.4

Mit Kerberos 5 1.4.1

1.4.1

Mit Kerberos 5 1.4.2

1.4.2

Mit Kerberos 5 1.4.3

1.4.3

Mit Kerberos 5 1.4.4

1.4.4

Mit Kerberos 5 1.5

1.5

Mit Kerberos 5 1.5.1

1.5.1

Mit Kerberos 5 1.5.2

1.5.2

Mit Kerberos 5 1.5.3

1.5.3

Mit Kerberos 5 1.6

1.6

Mit Kerberos 5 1.6.1

1.6.1

Mit Kerberos 5 1.6.2

1.6.2

References

http://docs.info.apple.com/article.html?artnum=307041

APPLE-SA-2007-11-14

[security-announce] 20070906 rPSA-2007-0179-2 krb5 krb5-server krb5-services krb5-test krb5-workstation

26676

Vendor Advisory

26680

Vendor Advisory

26684

Vendor Advisory

26691

Vendor Advisory

26697

Vendor Advisory

26699

Vendor Advisory

26700

Vendor Advisory

26705

Vendor Advisory

26713

Vendor Advisory

26728

Vendor Advisory

26783

Vendor Advisory

26792

Vendor Advisory

26822

Vendor Advisory

26896

Vendor Advisory

26987

Vendor Advisory

27043

Vendor Advisory

27081

Vendor Advisory

27146

Vendor Advisory

27643

Vendor Advisory

27756

29247

29270

GLSA-200710-01

3092

103060

201319

http://support.avaya.com/elmodocs2/security/ASA-2007-396.htm

http://web.mit.edu/Kerberos/advisories/MITKRB5-SA-2007-006.txt

DSA-1367

DSA-1368

GLSA-200709-01

VU#883632

US Government Resource

MDKSA-2007:174

MDKSA-2007:181

SUSE-SR:2007:019

SUSE-SR:2007:024

RHSA-2007:0858

RHSA-2007:0913

RHSA-2007:0951

20070906 rPSA-2007-0179-1 krb5 krb5-server krb5-services krb5-test krb5-workstation

20070912 ZDI-07-052: Multiple Kerberos Implementations Authentication Context Stack Overflow Vulnerability

25534

26444

1018647

2007-0026

USN-511-1

TA07-319A

US Government Resource

ADV-2007-3051

ADV-2007-3052

ADV-2007-3060

ADV-2007-3868

ADV-2008-0803

http://www.zerodayinitiative.com/advisories/ZDI-07-052.html

https://bugzilla.redhat.com/show_bug.cgi?id=250973

kerberos-rpcsecgss-bo(36437)

oval:org.mitre.oval:def:3162

oval:org.mitre.oval:def:9379

FEDORA-2007-2017

FEDORA-2008-1017

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