SB2017120303 - Multiple vulnerabilities in tor.eff Tor
Published: December 3, 2017 Updated: July 17, 2020
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 secuirty vulnerabilities.
1) NULL pointer dereference (CVE-ID: CVE-2017-8820)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error. A remote attacker can trigger denial of service conditions via a malformed descriptor, aka TROVE-2017-010.
2) Buffer overflow (CVE-ID: CVE-2017-8821)
The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.
In Tor before 0.2.5.16, 0.2.6 through 0.2.8 before 0.2.8.17, 0.2.9 before 0.2.9.14, 0.3.0 before 0.3.0.13, and 0.3.1 before 0.3.1.9, an attacker can cause a denial of service (application hang) via crafted PEM input that signifies a public key requiring a password, which triggers an attempt by the OpenSSL library to ask the user for the password, aka TROVE-2017-011.
3) Use-after-free (CVE-ID: CVE-2017-8823)
The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.
In Tor before 0.2.5.16, 0.2.6 through 0.2.8 before 0.2.8.17, 0.2.9 before 0.2.9.14, 0.3.0 before 0.3.0.13, and 0.3.1 before 0.3.1.9, there is a use-after-free in onion service v2 during intro-point expiration because the expiring list is mismanaged in certain error cases, aka TROVE-2017-013.
Remediation
Install update from vendor's website.