SB2021071002 - Gentoo update for Tor
Published: July 10, 2021
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 5 secuirty vulnerabilities.
1) Resource exhaustion (CVE-ID: CVE-2021-28089)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to application does not properly control consumption of internal resources when processing directory data. A remote attacker can force the Tor instance do consume huge amounts of CPU resources and perform a denial of service (DoS) attack.
2) Reachable Assertion (CVE-ID: CVE-2021-28090)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a reachable assertion in servers configured as directory authorities. A remote attacker can send specially crafted data to the server, trigger an assertions failure and crash it.
3) Information disclosure (CVE-ID: CVE-2021-34548)
The vulnerability allows a remote attacker to perform spoofing attack.
The vulnerability exists due to incorrect processing of user-supplied data. A remote attacker can spoof RELAY_END or RELAY_RESOLVED cell on half-closed streams, which would allow a relay on a circuit to end a stream that wasn't actually built with it.
4) Resource management error (CVE-ID: CVE-2021-34549)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to improper management of internal resources within the naive unkeyed hash function. A remote attacker can construct circuits with chosen circuit IDs, to create collisions and make the hash table inefficient, resulting in denial of service condition.
5) Out-of-bounds read (CVE-ID: CVE-2021-34550)
The vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to a boundary condition during v3 onion service descriptor parsing. A remote attacker can create an onion service descriptor that would crash any client that tried to visit it.
Remediation
Install update from vendor's website.