SB2020072817 - Gentoo update for Dropbear

Description

This security bulletin contains information about 3 vulnerabilities.

1) Resource exhaustion (CVE-ID: CVE-2018-0739)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a remote attacker to cause DoS condition on the target system.

The weakness exists due to excessive stack memory consumption. A remote attacker can cause the service to crash.

2) Information disclosure (CVE-ID: CVE-2018-12437)

CWE-ID: CWE-200 - Exposure of sensitive information to an unauthorized actor

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local attacker to obtain potentially sensitive information.

The vulnerability exists in the libtomcrypt library due to a leakage of information through memory caches when the library uses a private key to create Elliptic Curve Digital Signature Algorithm (ECDSA) signatures. A local attacker can conduct a memory-cache side-channel attack and recover sensitive information, such ECDSA private keys, which could be used to conduct further attacks.

3) Security restrictions bypass (CVE-ID: CVE-2018-20685)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a remote attacker to bypass security restrictions on the target system.

The vulnerability exists due to improper validation of filenames by the scp.c source code file in the SCP client . A remote unauthenticated attacker can trick the victim into accessing a file with the filename of . or an empty filename from an attacker-controlled Secure Shell (SSH) server to bypass access restrictions on the system, which could be used to conduct further attacks.

Remediation

Install update from vendor's website.

References

• https://security.gentoo.org/
• https://security.gentoo.org/glsa/202007-53