Is "WebP → JPEG Downloader" on Firefox Add-ons Safe to Install?

FAST · firefox · v2.1.0

webp is a vile and horrible file format invented by the dark wizards at G*ogle. We hate it. This extension quietly converts all webps to jpeg before downloading them. Never have to worry about it again.

Risk Assessment

Analyzed
84.84
out of 100
HIGH

23 security findings detected across all analyzers

Firefox extension requesting 3 permissions

Severity Breakdown

0
Critical
8
High
15
Medium
0
Low
0
Info

Finding Categories

8
Malware Signatures
2
Network
12
IoC Indicators

YARA Rules Matched

4 rules(8 hits)
postinstall file download postinstall obfuscation postinstall file manipulation postinstall network communication

Requested Permissions

3 permissions
<all_urls>

Access and modify data on every website you visit

Dangerous
downloads

Manage, modify, and monitor downloads

High
contextMenus
Low

About This Extension

webp is a vile and horrible file format invented by the dark wizards at G*ogle. We hate it. This extension quietly converts all webps to jpeg before downloading them. Never have to worry about it again.

Detailed Findings

11 total

YARA Rule Matches

4 rules

Indicators of Compromise

Network indicators, suspicious strings, and potential IoCs extracted during analysis

URLs
1
Domains
10
Strings
12

All Indicators · 12

Domain
detected Domain: readme.md

XIOC detected Domain: readme.md

extracted_from_files

Domain
detected Domain: a.download

XIOC detected Domain: a.download

extracted_from_files

Domain
detected Domain: a.click

XIOC detected Domain: a.click

extracted_from_files

URL
detected URL: http://addons.mozilla.org/ca/crl.pem0N

XIOC detected URL: http://addons.mozilla.org/ca/crl.pem0N

extracted_from_files

Hash
detected MD5 Hash: b29d05d374cb46c83434b8bdabaacbe6

XIOC detected MD5 Hash: b29d05d374cb46c83434b8bdabaacbe6

extracted_from_files

Domain
detected Domain: signingca1.addons.mozilla.org

XIOC detected Domain: signingca1.addons.mozilla.org

extracted_from_files

Domain
detected Domain: mozilla.com

XIOC detected Domain: mozilla.com

extracted_from_files

Domain
detected Domain: content-signature.mozilla.org

XIOC detected Domain: content-signature.mozilla.org

extracted_from_files

Domain
detected Domain: tc12f81beb6f929d5983b6f9de6df5d9a.b29d05d374cb46c83434b8bdabaacbe6.addons.mozilla.org

XIOC detected Domain: tc12f81beb6f929d5983b6f9de6df5d9a.b29d05d374cb46c83434b8bdabaacbe6.addons.mozilla.org

extracted_from_files

Domain
detected Domain: tab.id

XIOC detected Domain: tab.id

extracted_from_files

Domain
detected Domain: item.id

XIOC detected Domain: item.id

extracted_from_files

Domain
detected Domain: browser.downloads.download

XIOC detected Domain: browser.downloads.download

extracted_from_files

Security Analysis Summary

Security Analysis Overview

WebP → JPEG Downloader is a Firefox Add-ons extension published by FAST. Version 2.1.0 has been analyzed by the Risky Plugins security platform, receiving a risk score of 84.84/100 (HIGH risk) based on 23 security findings.

Risk Assessment

This extension presents critical security risk. Severe issues were detected, potentially including malware indicators, exposed secrets, or dangerous behaviors. Installation is strongly discouraged until these issues are addressed.

Findings Breakdown

  • High: 8 finding(s)
  • Medium: 15 finding(s)

What Was Analyzed

The security assessment covers multiple analysis categories:

  • Malware Detection: YARA rule matching against 2,400+ malware signatures
  • Secret Detection: Scanning for exposed API keys, tokens, and credentials
  • Static Analysis: Code-level security analysis for common vulnerability patterns
  • Network Analysis: Detection of suspicious network communications and endpoints
  • Obfuscation Detection: Identification of code obfuscation techniques

Developer Information

WebP → JPEG Downloader is published by FAST on the Firefox Add-ons marketplace. The extension has approximately 31 users.

Recommendation

This extension is not recommended for installation without thorough manual review. Consider alternatives with lower risk scores, or contact the developer to address the identified security concerns.

Frequently Asked Questions