It’s Never Simple Until It Is Dell UnityVSA Pre‑Auth Command...

[carlospolop]

🤖 Automated Content Update

This PR was automatically generated by the HackTricks News Bot based on a technical blog post.

📝 Source Information

• Blog URL: https://labs.watchtowr.com/its-never-simple-until-it-is-dell-unityvsa-pre-auth-command-injection-cve-2025-36604/
• Blog Title: It’s Never Simple Until It Is: Dell UnityVSA Pre‑Auth Command Injection (CVE‑2025‑36604)
• Suggested Section: Pentesting Web > Command Injection > Perl/mod_perl backticks (Apache mod_perl handler reachability)

🎯 Content Summary

Target/Product: Dell UnityVSA (Virtual Storage Appliance). Versions examined via patch‑diff: 5.4.0.0.5.094 (known vulnerable) and 5.5.0.0.5.259 (contained additional vulnerable path). Fixed in 5.5.1 per Dell PSIRT advisory DSA‑2025‑281.
<br/...

🔧 Technical Details

Patch‑diff driven vuln hunting: Compare “vulnerable” vs “patched” builds and focus on modules that build shell commands. Look for inconsistent escaping across branches (e.g., a single if ($type eq "login") path that appends attacker‑controlled data). Backticks are high‑value sinks.

Call‑graph to sink reachability: Start from the sink (getCASURL) and enumerate callers. Observe getCASLoginURL(..., type="login") and trace back to make_return_address($r) where $r->uri() enters. Confirm the web server configuration (PerlModule MOD_SEC_EMC::AccessHandler) ensures the handler executes.

Triggering the pre‑auth path reliably: Omit the auth cookie to force the login redirect so type=="login" is guaranteed. Use a resolvable URI within the handler’s scope; otherwise Apache won’t invoke the module and the sink isn’t reached.

General defensive pattern: Avoid ...

🤖 Agent Actions

I analyzed the repository and updated the most relevant existing page instead of creating a new one.

What I updated

• File: src/pentesting-web/command-injection.md

• Change: Added a new subsection “Perl backticks/qx// sinks in Apache mod_perl handlers (reachability and exploitation)” that:

  • Documents risky Perl execution primitives (backticks/qx//, system with single string, open with pipe, IPC::Open3 with single string).
  • Explains mod_perl handler reachability and the importance of handler registration in httpd.conf, pre-auth login flow triggering (type == "login"), and the resolvable path nuance for handler execution.
  • Provides an exploitation workflow and a concise HTTP PoC example.
  • Adds hardening guidance (favor system LIST/argument vectors, avoid backticks, consistent escaping, allowlists).
  • Highlights patch-diff hunting techniques and call-graph tracing to confirm pre-auth reachability.
  • Summarizes the Dell UnityVSA real-world case (CVE-2025-36604) as a concrete example without duplicating the entire blog.

• References: Appended new references at the end of the same file:

  • watchTowr blog post
  • Dell PSIRT advisory (DSA‑2025‑281)
  • watchTowr Detection Artefact Generator GitHub repository

Why here

• This belongs under Pentesting Web > Command Injection because it generalizes a technique (Perl backticks in mod_perl handlers) and its reachability patterns, not a product- or CVE-specific page.
• There was no existing mod_perl/Perl-specific section in HackTricks’ command injection coverage, and adding it enriches the general methodology.

Checks performed

• Read ≥5 relevant files to align structure/style and find the best location:
  • src/pentesting-web/command-injection.md
  • src/network-services-pentesting/pentesting-web/cgi.md
  • src/pentesting-web/web-vulnerabilities-methodology.md
  • src/network-services-pentesting/pentesting-web/ruby-tricks.md
  • src/pentesting-web/pocs-and-polygloths-cheatsheet/README.md
• Kept existing structure, added a concise, technique-focused section, and preserved the training banner and existing references.

No new files were created, and only the necessary, high-value technical content was added.

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This PR was automatically created by the HackTricks Feed Bot. Please review the changes carefully before merging.

[carlospolop]

🔗 Additional Context

Original Blog Post: https://labs.watchtowr.com/its-never-simple-until-it-is-dell-unityvsa-pre-auth-command-injection-cve-2025-36604/

Content Categories: Based on the analysis, this content was categorized under "Pentesting Web > Command Injection > Perl/mod_perl backticks (Apache mod_perl handler reachability)".

Repository Maintenance:

• MD Files Formatting: 901 files processed

Review Notes:

• This content was automatically processed and may require human review for accuracy
• Check that the placement within the repository structure is appropriate
• Verify that all technical details are correct and up-to-date
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Bot Version: HackTricks News Bot v1.0