1. Ubuntu Security Notices
  2. USN-5308-1

USN-5308-1: libssh2 vulnerabilities

Publication date

7 March 2022

Overview

Several security issues were fixed in libssh2.

Releases

Packages

  • libssh2 - Client-side C library implementing the SSH2 protocol

Details

It was discovered that libssh2 mishandled certain input. If libssh2 were
used to connect to a malicious or compromised SSH server, a remote,
unauthenticated attacker could possibly execute arbitrary code on the client
system. (CVE-2019-3855)

It was discovered that libssh2 incorrectly handled prompt requests. A
remote attacker could possibly use this issue to execute arbitrary code.
(CVE-2019-3856)

It was discovered that libssh2 incorrectly handled SSH_MSG_CHANNEL_REQUEST
packets. A remote attacker could possibly use this issue to execute
arbitrary code, cause a denial of service, or obtain sensitive information.
(CVE-2019-3857, CVE-2019-3862)

It was discovered that libssh2 incorrectly handled specially crafted SFTP
packets. A remote attacker could possibly use this issue to...

It was discovered that libssh2 mishandled certain input. If libssh2 were
used to connect to a malicious or compromised SSH server, a remote,
unauthenticated attacker could possibly execute arbitrary code on the client
system. (CVE-2019-3855)

It was discovered that libssh2 incorrectly handled prompt requests. A
remote attacker could possibly use this issue to execute arbitrary code.
(CVE-2019-3856)

It was discovered that libssh2 incorrectly handled SSH_MSG_CHANNEL_REQUEST
packets. A remote attacker could possibly use this issue to execute
arbitrary code, cause a denial of service, or obtain sensitive information.
(CVE-2019-3857, CVE-2019-3862)

It was discovered that libssh2 incorrectly handled specially crafted SFTP
packets. A remote attacker could possibly use this issue to cause a denial
of service or obtain sensitive information. (CVE-2019-3858)

It was discovered that libssh2 incorrectly handled certain specially
crafted packets. A remote attacker could possibly use this issue to cause a
denial of service or obtain sensitive information. (CVE-2019-3859)

It was discovered that libssh2 incorrectly handled SFTP packets with empty
payloads. A remote attacker could possibly use this issue to cause a denial
of service or obtain sensitive information. (CVE-2019-3860)

It was discovered that libssh2 incorrectly handled padding values in SSH
packets. A remote attacker could possibly use this issue to cause a denial
of service or obtain sensitive information. (CVE-2019-3861)

It was discovered that libssh2 incorrectly handled interactive response
messages length. A remote attacker could possibly use this issue to execute
arbitrary code. (CVE-2019-3863)

It was discovered that libssh2 incorrectly handled the Diffie Hellman key
exchange. A remote attacker could possibly use this issue to cause a denial
of service or obtain sensitive information. (CVE-2019-13115)

It was discovered that libssh2 incorrectly handled bound checks in
SSH_MSG_DISCONNECT. A remote attacker could possibly use this issue to
cause a denial of service or obtain sensitive information. (CVE-2019-17498)

Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
16.04 xenial libssh2-1 –  1.5.0-2ubuntu0.1+esm1  

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References

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