DirectLogic H2-DM1E: Authentication Bypass by Capture-replay
CVE-2024-43099 is a high-severity authentication bypass by capture-replay vulnerability in DirectLogic H2-DM1E from AutomationDirect, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected DirectLogic H2-DM1E versions: 2.8.0 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.28% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of DirectLogic H2-DM1E you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| AutomationDirect | DirectLogic H2-DM1E | 2.8.0 and earlier | Not stated |
| Automationdirect | h2-dm1e_firmware | 2.8.0 and earlier | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (hq.dhs.gov).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA (hq.dhs.gov) |
| CVSS 3.1 | 8.8 | High | CNA (hq.dhs.gov) |
Official description
The session hijacking attack targets the application layer's control mechanism, which manages authenticated sessions between a host PC and a PLC. During such sessions, a session key is utilized to maintain security. However, if an attacker captures this session key, they can inject traffic into an ongoing authenticated session. To successfully achieve this, the attacker also needs to spoof both the IP address and MAC address of the originating host which is typical of a session-based attack.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authentication Bypass by Capture-replay
A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).
How developers prevent this class of flaw
- Utilize some sequence or time stamping functionality along with a checksum which takes this into account in order to ensure that messages can be parsed only once.
- Since any attacker who can listen to traffic can see sequence numbers, it is necessary to sign messages with some kind of cryptography to ensure that sequence numbers are not simply doctored along with content.
More Authentication Bypass by Capture-replay vulnerabilities (CWE-294)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in DirectLogic H2-DM1E
- 8.8 High severity
Recent Authentication Bypass by Capture-replay vulnerabilities
- 7.3 High severity
- 8.2 High severity
- 8.4 High severity
- 8.7 High severity
- 8.1 High severity
- 7.8 High severity
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