Description

A security flaw has been discovered in lin-snow Ech0 up to 5.4.1. Affected by this issue is the function MD5Encrypt of the file internal/util/crypto/crypto.go. Performing a manipulation results in risky cryptographic algorithm. Remote exploitation of the attack is possible. The complexity of an attack is rather high. The exploitation is known to be difficult. Upgrading to version 5.4.2 can resolve this issue. The patch is named 9ce19a3b0d0765086a655f45d3a706ec1810404f. It is recommended to upgrade the affected component.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "3.7",
  "pubDate": "2026-08-20T20:17:47.253Z",
  "pubdate": "2026-08-20T20:17:47.253Z",
  "executiveSummary": "A security vulnerability has been identified in lin-snow Ech0 up to version 5.4.1, specifically within the cryptographic utility functions. The flaw involves the use of a weak and cryptographically broken algorithm, namely MD5, implemented inside the MD5Encrypt function located in internal/util/crypto/crypto.go.\nThe primary impact of this vulnerability is the exposure of sensitive data to cryptographic attacks such as collision attacks and brute-force cracking, potentially leading to unauthorized data exposure or integrity compromise. The affected product is lin-snow Ech0 in versions up to 5.4.1.\nRemote exploitation of this vulnerability is feasible, allowing threat actors across a network to interact with the vulnerable component. However, the complexity of an attack is rather high, and the overall exploitation is known to be difficult, requiring specific conditions or context to successfully abuse the weak hashing mechanism.\nRisk implications include the potential compromise of sensitive values processed by the cryptographic function. Remediation requires upgrading the affected component to version 5.4.2, which incorporates the official security patch identified by commit hash 9ce19a3b0d0765086a655f45d3a706ec1810404f.",
  "technicalDetails": "The vulnerability resides in the internal/util/crypto/crypto.go file of the lin-snow Ech0 application, specifically inside the MD5Encrypt function. The root cause of the security flaw is the reliance on the outdated and cryptographically insecure MD5 hashing algorithm for encryption or sensitive data processing. MD5 has been deprecated for security-sensitive operations for many years due to its susceptibility to collision vulnerabilities and rapid brute-force analysis via modern computational hardware.\nThe vulnerable component is exposed via network vectors, enabling remote exploitation under specific conditions. Because the application utilizes MD5Encrypt to handle sensitive data or cryptographic transformations, an attacker capable of observing or manipulating input and output data can leverage the cryptographic weaknesses of the algorithm. The attack flow involves the adversary interacting with remote interfaces that invoke the vulnerable function, supplying or intercepting data processed by MD5Encrypt.\nAlthough remote exploitation is possible, the exploitation complexity is rather high and the exploitation process is known to be difficult. This suggests that successful exploitation may depend on specific environmental factors, privileged insight into the data structures, or chaining with other weaknesses to achieve a tangible impact. The payload behavior inherently relies on exploiting weak digest generation, allowing potential signature forgery, data tampering, or unauthorized reconstruction of original inputs if the hashed values are treated as secure cryptographic protections.\nThe affected versions include lin-snow Ech0 up to version 5.4.1. The issue is fully resolved in version 5.4.2 by applying the security patch associated with commit 9ce19a3b0d0765086a655f45d3a706ec1810404f, which replaces or secures the weak hashing implementation."
}