Daemon exit via mishandled pending DNS states
Published Jan 24, 2020 · Updated Aug 6, 2024
Denial of service in The Tor Project Tor before 0.2.4.26 and 0.2.5.x before 0.2.5.11 allows remote attackers to exit the daemon. During high DNS load, the exit-node DNS resolver mishandles pending-connection resolve states and reaches an assertion failure instead of safely rejecting crafted packets. The target must operate as an exit node processing attacker-controlled resolution traffic; exploitation crashes the Tor daemon without reported data disclosure or modification.
Summary
What happened
Denial of service in The Tor Project Tor before 0.2.4.26 and 0.2.5.x before 0.2.5.11 allows remote attackers to exit the daemon. During high DNS load, the exit-node DNS resolver mishandles pending-connection resolve states and reaches an assertion failure instead of safely rejecting crafted packets. The target must operate as an exit node processing attacker-controlled resolution traffic; exploitation crashes the Tor daemon without reported data disclosure or modification.
The record
- CVE
- CVE-2015-2689
- Published
- Jan 24, 2020
- Updated
- Aug 6, 2024
- Vendor
- The Tor Project
- Product
- Tor
- Classifications
- CWE-20, T1498
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 24, 2020CVE publishedPublication date reported by the CVE source.
- Aug 6, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0.2.5.x before 0.2.5.11
- Affected versionversion=before 0.2.4.26
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo