CVE-2019-3859 - Out-of-bounds Read

Severity

64%

Complexity

99%

Confidentiality

81%

An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the _libssh2_packet_require and _libssh2_packet_requirev functions. A remote attacker who compromises a SSH server may be able to cause a Denial of Service or read data in the client memory.

An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the _libssh2_packet_require and _libssh2_packet_requirev functions. A remote attacker who compromises a SSH server may be able to cause a Denial of Service or read data in the client memory.

CVSS 3.0 Base Score 9.1. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H).

CVSS 2.0 Base Score 6.4. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (AV:N/AC:L/Au:N/C:P/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

Overview

First reported 5 years ago

2019-03-21 16:01:00

Last updated 5 years ago

2019-07-25 21:15:00

Affected Software

Fedora 28

28

Fedora 29

29

Debian Linux 8.0 (Jessie)

8.0

Debian Linux 9.0

9.0

openSUSE Leap 15.0

15.0

openSUSE Leap 42.3

42.3

References

openSUSE-SU-2019:1075

Mailing List, Third Party Advisory

openSUSE-SU-2019:1109

Mailing List, Third Party Advisory

openSUSE-SU-2019:1290

Mailing List, Third Party Advisory

openSUSE-SU-2019:1291

Mailing List, Third Party Advisory

http://packetstormsecurity.com/files/152136/Slackware-Security-Advisory-libssh2-Updates.html

Patch, Third Party Advisory, VDB Entry

[oss-security] 20190318 [SECURITY ADVISORIES] libssh2

Mailing List, Patch, Third Party Advisory

107485

Third Party Advisory, VDB Entry

https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-3859

Issue Tracking, Patch, Third Party Advisory

[debian-lts-announce] 20190326 [SECURITY] [DLA 1730-1] libssh2 security update

Mailing List, Third Party Advisory

[debian-lts-announce] 20190402 [SECURITY] [DLA 1730-2] libssh2 regression update

Mailing List, Third Party Advisory

[debian-lts-announce] 20190725 [SECURITY] [DLA 1730-3] libssh2 regression update

FEDORA-2019-3348cb4934

Mailing List, Release Notes, Third Party Advisory

FEDORA-2019-f31c14682f

Release Notes, Third Party Advisory

20190415 [SECURITY] [DSA 4431-1] libssh2 security update

Mailing List, Third Party Advisory

20190319 [slackware-security] libssh2 (SSA:2019-077-01)

Mailing List, Patch, Third Party Advisory

https://security.netapp.com/advisory/ntap-20190327-0005/

Third Party Advisory

https://www.broadcom.com/support/fibre-channel-networking/security-advisories/brocade-security-advisory-2019-767

Third Party Advisory

DSA-4431

Third Party Advisory

https://www.libssh2.org/CVE-2019-3859.html

Vendor Advisory

https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html

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