SB2017120305 - Fedora 27 update for tor
Published: December 3, 2017 Updated: April 24, 2025
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 5 secuirty vulnerabilities.
1) Input validation error (CVE-ID: CVE-2017-8819)
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, the replay-cache protection mechanism is ineffective for v2 onion services, aka TROVE-2017-009. An attacker can send many INTRODUCE2 cells to trigger this issue.
2) 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.
3) 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.
4) Input validation error (CVE-ID: CVE-2017-8822)
The vulnerability allows a remote non-authenticated attacker to gain access to sensitive information.
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, relays (that have incompletely downloaded descriptors) can pick themselves in a circuit path, leading to a degradation of anonymity, aka TROVE-2017-012.
5) 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.