Memory disclosure or service interruption via DNS parsing
Published Apr 22, 2021 · Updated Aug 4, 2024
Improper null termination in Siemens Nucleus RTOS DNS clients allows man-in-the-middle attackers to leak memory or interrupt service. The domain-label parser fails to validate that a name in a DNS response is null-terminated, so a malformed response triggers a read past its allocated structure. Exploitation requires a privileged network position to manipulate a DNS response; the resulting out-of-bounds read can expose adjacent memory or stop the affected device.
Summary
What happened
Improper null termination in Siemens Nucleus RTOS DNS clients allows man-in-the-middle attackers to leak memory or interrupt service. The domain-label parser fails to validate that a name in a DNS response is null-terminated, so a malformed response triggers a read past its allocated structure. Exploitation requires a privileged network position to manipulate a DNS response; the resulting out-of-bounds read can expose adjacent memory or stop the affected device.
The record
- CVE
- CVE-2020-27736
- Published
- Apr 22, 2021
- Updated
- Aug 4, 2024
- Vendor
- Siemens
- Product
- TALON TC Compact (BACnet)
- Classifications
- CWE-170, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 22, 2021CVE publishedPublication date reported by the CVE source.
- Aug 4, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=All versions < V3.5.5
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Technologies
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Your stack
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