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gentooGentoo FoundationGLSA-202004-08
HistoryApr 10, 2020 - 12:00 a.m.

libssh: Denial of service

2020-04-1000:00:00
Gentoo Foundation
security.gentoo.org
11

5.3 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

LOW

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

5 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:N/I:N/A:P

0.004 Low

EPSS

Percentile

73.9%

Background

libssh is a multiplatform C library implementing the SSHv2 protocol on client and server side.

Description

It was discovered that libssh could crash when AES-CTR ciphers are used.

Impact

A remote attacker running a malicious client or server could possibly crash the counterpart implemented with libssh and cause a Denial of Service condition.

Workaround

Disable AES-CTR ciphers. If you implement a server using libssh it is recommended to use a prefork model so each session runs in an own process.

Resolution

All libssh users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-libs/libssh-0.9.4"
OSVersionArchitecturePackageVersionFilename
Gentooanyallnet-libs/libssh< 0.9.4UNKNOWN

5.3 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

LOW

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

5 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:N/I:N/A:P

0.004 Low

EPSS

Percentile

73.9%