Security - https://f-droid.org BeaverCheck Audit

B

Security Headers

6 of 10 headers properly configured

REVIEW

6 of 10 headers properly configured

HSTS is missing includeSubDomains

Without includeSubDomains, subdomains can still be accessed over HTTP.

Got: max-age=63072000 Expected: max-age=31536000; includeSubDomains

X-Content-Type-Options is properly configured

Got: nosniff

X-Frame-Options is properly configured

Got: sameorigin

Referrer-Policy is properly configured

Got: strict-origin

Permissions-Policy is set

Got: accelerometer=(), ambient-light-sensor=(), autoplay=(), battery=(), bluetooth=(), browsing-topics=(), camera=(), ch-ua=(), clipboard-read=(), clipboard-write=(), conversion-measurement=(), display-capture=(), document-domain=(), document-write=(), encrypted-media=(), execution-while-not-rendered=(), execution-while-out-of-viewport=(), focus-without-user-activation=(), fullscreen=(), gamepad=(), geolocation=(), gyroscope=(), hid=(), idle-detection=(), interest-cohort=(), keyboard-map=(), local-fonts=(), magnetometer=(), microphone=(), midi=(), navigation-override=(), payment=(), picture-in-picture=(), publickey-credentials-get=(), screen-wake-lock=(), serial=(), speaker=(), speaker-selection=(), sync-xhr=(), trust-token-redemption=(), usb=(), wake-lock=(), webauthn=(), web-share=(), window-placement=(), vr=(), xr=(), xr-spatial-tracking=(),

Content-Security-Policy is present

Got: default-src 'none';base-uri 'self';block-all-mixed-content;connect-src 'self';fo…

Cross-Origin-Opener-Policy header is missing

COOP isolates your browsing context, preventing cross-origin side-channel attacks. Set to 'same-origin'.

Expected: same-origin

Cross-Origin-Embedder-Policy header is missing

COEP prevents loading cross-origin resources without explicit permission. Required for SharedArrayBuffer and high-resolution timers.

Expected: require-corp

X-Powered-By header is not present

Server header reveals version information

The Server header discloses the software version, aiding attackers in targeting known vulnerabilities. Remove the version number.

Got: nginx/1.22.1

Without includeSubDomains, subdomains can still be accessed over HTTP.

Expected: max-age=31536000; includeSubDomains

Why this matters

Without includeSubDomains, a forgotten dev subdomain over HTTP can set malicious cookies that ride to the apex.

Learn more ▾

HSTS without includeSubDomains protects only the exact domain. Cookies set on a non-HSTS subdomain can ride to the apex via cookie-scope attacks. The fix is one directive append. Verify all subdomains support HTTPS first — adding includeSubDomains to a domain with HTTP-only subdomains breaks them.

Source: RFC 6797

COOP isolates your browsing context, preventing cross-origin side-channel attacks. Set to 'same-origin'.

Expected: same-origin

Why this matters

COOP isolates your top-level browsing context from cross-origin windows — without it, popup-based side-channel attacks remain possible.

Learn more ▾

Cross-Origin-Opener-Policy: same-origin prevents cross-origin pages from sharing a browsing-context group with yours. This blocks cross-window references that enable Spectre-style timing attacks and tab-nabbing. Required if you want to enable SharedArrayBuffer.

Source: MDN / web.dev

COEP prevents loading cross-origin resources without explicit permission. Required for SharedArrayBuffer and high-resolution timers.

Expected: require-corp

Why this matters

COEP enforces that all embedded resources opt-in to cross-origin embedding — required for cross-origin isolation features.

Learn more ▾

Cross-Origin-Embedder-Policy: require-corp ensures every embedded resource (script, iframe, image) explicitly allows being loaded cross-origin. Combined with COOP, this enables the cross-origin-isolated context that unlocks SharedArrayBuffer, high-resolution timers, and other powerful APIs.

Source: MDN / web.dev

The Server header discloses the software version, aiding attackers in targeting known vulnerabilities. Remove the version number.

Why this matters

Server: nginx/1.18.0 tells attackers exactly which CVEs to test — strip the version string.

Learn more ▾

Server version disclosure helps attackers select exploits matching your stack. Configure your server to omit the version (nginx: `server_tokens off;`, Apache: `ServerTokens Prod`). Doesn't fix vulnerabilities but removes the easy reconnaissance step.

Source: OWASP

B

CORS Configuration

No CORS headers

REVIEW

No CORS headers

No CORS headers present — secure default

CORS Configuration ✓ Secure

No CORS headers detected.

Cross-origin requests are blocked by browser same-origin policy.

Origin reflection test

Some servers mirror the request Origin header, which can be exploited. Test manually:

curl -sI -H "Origin: https://evil.com" <url> | grep -i access-control

A+

Content Security Policy

8 of 10 CSP checks passed

PASS

8 of 10 CSP checks passed

Raw CSP policy

Got: default-src 'none';base-uri 'self';block-all-mixed-content;connect-src 'self';font-src 'self';form-action 'self' https://search.f-droid.org;frame-ancestors 'self';img-src 'self' https://f-droid.org;manifest-src 'self';media-src 'self';script-src 'self';style-src 'self' 'unsafe-inline';

default-src directive is set

Got: default-src 'none'

No 'unsafe-inline' in script source

No 'unsafe-eval' in script source

No wildcard in script source

object-src falls back to default-src

base-uri is properly restricted

Got: base-uri 'self'

frame-ancestors directive is set

Got: frame-ancestors 'self'

form-action directive is set

Got: form-action 'self' https://search.f-droid.org

upgrade-insecure-requests is not set

This directive upgrades HTTP resources to HTTPS automatically, preventing mixed content.

Expected: upgrade-insecure-requests

This directive upgrades HTTP resources to HTTPS automatically, preventing mixed content.

Expected: upgrade-insecure-requests

Why this matters

Without upgrade-insecure-requests, any HTTP subresource link survives as a mixed-content warning instead of auto-upgrading.

Learn more ▾

Adding `upgrade-insecure-requests` to your CSP turns every http:// subresource fetch into https:// at the browser layer. One-line defense against accidental mixed content from legacy links or third-party widgets.

Source: MDN CSP

Parsed Policy

default-src 'none'

base-uri 'self'

block-all-mixed-content

connect-src 'self'

font-src 'self'

form-action 'self'https://search.f-droid.org

frame-ancestors 'self'

img-src 'self'https://f-droid.org

manifest-src 'self'

media-src 'self'

script-src 'self'

style-src 'self''unsafe-inline'

A+

TLS & Certificates

TLS 1.3, 7 checks passed

PASS

TLS 1.3, 7 checks passed

TLS 1.3 is used

Got: TLS 1.3

Strong cipher suite is used

Got: TLS_AES_256_GCM_SHA384

HTTP/2 is not negotiated

HTTP/2 provides multiplexing and header compression for better performance.

Got: http/1.1

Certificate is valid (expires in 68 days)

Got: 2026-06-29T01:03:28Z

Certificate chain has 2 certificates

Certificate uses modern signature algorithm

Got: SHA256-RSA

Certificate covers 8 domain(s)

Got: f-droid.com, f-droid.org, fdroid.com, fdroid.org, www.f-droid.com, www.f-droid.org, www.fdroid.com, www.fdroid.org

Certificate is issued by a trusted CA

Got: CN=R13,O=Let's Encrypt,C=US

HTTP/2 provides multiplexing and header compression for better performance.

Why this matters

HTTP/1.1 forces the browser to make sequential requests, multiplying latency on every page.

Learn more ▾

HTTP/2 (and HTTP/3) multiplex many requests over a single connection, eliminating head-of-line blocking. HTTP/1.1 forces the browser to either queue requests or open many parallel connections — both worse. Most modern web servers support HTTP/2 with one config line.

Source: MDN Web Docs

Connection

Protocol

TLS 1.3

Cipher Suite

TLS_AES_256_GCM_SHA384

HTTP Version

HTTP/1.1

Certificate Chain

Leaf Certificate

Subject CN=f-droid.orgIssuer CN=R13,O=Let's Encrypt,C=USValid 2026-03-31T01:03:29Z → 2026-06-29T01:03:28ZExpires in 68 days SANs f-droid.com, f-droid.org, fdroid.com, fdroid.org, www.f-droid.com, www.f-droid.org, www.fdroid.com, www.fdroid.orgSignature SHA256-RSASerial 674f0e93614170d353ace89627a8fa5b254

Intermediate (CA Certificate)

Subject CN=R13,O=Let's Encrypt,C=USIssuer CN=ISRG Root X1,O=Internet Security Research Group,C=USValid 2024-03-13T00:00:00Z → 2027-03-12T23:59:59ZExpires in 324 days Signature SHA256-RSASerial 5a00f212d8d4b480f3924157ea298305

A+

Cookie Security

No cookies set — no cookie security risks

PASS

No cookies set — no cookie security risks

No cookies detected — no cookie security risks to report.

A+

Subresource Integrity

No external resources

PASS

No external resources

No external resources to protect

SRI Coverage No external resources — SRI not applicable

A+

JS Library Vulnerabilities

No known vulnerabilities

PASS

No known vulnerabilities

No known JavaScript library vulnerabilities detected

No known JavaScript library vulnerabilities detected.

A+

Information Leakage

No exposures

PASS

No exposures

security.txt is present — good practice

No sensitive files exposed

No sensitive files exposed — all paths returned 404.

Path	Status	Category	Risk
/.git/HEAD	✓ Not found	Version Control	—
/.git/config	✓ Not found	Version Control	—
/.svn/entries	✓ Not found	Version Control	—
/.env	✓ Not found	Configuration	—
/.env.local	✓ Not found	Configuration	—
/.env.production	✓ Not found	Configuration	—
/wp-config.php	✓ Not found	Configuration	—
/.htaccess	✓ Not found	Configuration	—
/phpinfo.php	✓ Not found	Debug	—
/server-status	✓ Not found	Debug	—
/server-info	✓ Not found	Debug	—
/.well-known/security.txt	✗ Exposed	Security Policy	Info

A+

Email Security

DMARC: reject

PASS

DMARC: reject

DMARC policy is reject — strongest protection

DMARC

Policy reject — strongest protection Record v=DMARC1; p=reject; rua=mailto:mailauth-reports@f-droid.org

A+

Permissions-Policy

48 directives, 0 missing

PASS

48 directives, 0 missing

accelerometer=() — blocked for all origins

ambient-light-sensor=() — blocked for all origins

autoplay=() — blocked for all origins

battery=() — blocked for all origins

bluetooth=() — blocked for all origins

browsing-topics=() — blocked for all origins

camera=() — blocked for all origins

ch-ua=() — blocked for all origins

clipboard-read=() — blocked for all origins

clipboard-write=() — blocked for all origins

conversion-measurement=() — blocked for all origins

display-capture=() — blocked for all origins

document-domain=() — blocked for all origins

document-write=() — blocked for all origins

encrypted-media=() — blocked for all origins

execution-while-not-rendered=() — blocked for all origins

execution-while-out-of-viewport=() — blocked for all origins

focus-without-user-activation=() — blocked for all origins

fullscreen=() — blocked for all origins

gamepad=() — blocked for all origins

geolocation=() — blocked for all origins

gyroscope=() — blocked for all origins

hid=() — blocked for all origins

idle-detection=() — blocked for all origins

interest-cohort=() — blocked for all origins

keyboard-map=() — blocked for all origins

local-fonts=() — blocked for all origins

magnetometer=() — blocked for all origins

microphone=() — blocked for all origins

midi=() — blocked for all origins

navigation-override=() — blocked for all origins

payment=() — blocked for all origins

picture-in-picture=() — blocked for all origins

publickey-credentials-get=() — blocked for all origins

screen-wake-lock=() — blocked for all origins

serial=() — blocked for all origins

speaker=() — blocked for all origins

speaker-selection=() — blocked for all origins

sync-xhr=() — blocked for all origins

trust-token-redemption=() — blocked for all origins

usb=() — blocked for all origins

wake-lock=() — blocked for all origins

webauthn=() — blocked for all origins

web-share=() — blocked for all origins

window-placement=() — blocked for all origins

vr=() — blocked for all origins

xr=() — blocked for all origins

xr-spatial-tracking=() — blocked for all origins

Raw Header

accelerometer=() ambient-light-sensor=() autoplay=() battery=() bluetooth=() browsing-topics=() camera=() ch-ua=() clipboard-read=() clipboard-write=() conversion-measurement=() display-capture=() document-domain=() document-write=() encrypted-media=() execution-while-not-rendered=() execution-while-out-of-viewport=() focus-without-user-activation=() fullscreen=() gamepad=() geolocation=() gyroscope=() hid=() idle-detection=() interest-cohort=() keyboard-map=() local-fonts=() magnetometer=() microphone=() midi=() navigation-override=() payment=() picture-in-picture=() publickey-credentials-get=() screen-wake-lock=() serial=() speaker=() speaker-selection=() sync-xhr=() trust-token-redemption=() usb=() wake-lock=() webauthn=() web-share=() window-placement=() vr=() xr=() xr-spatial-tracking=()

Feature Permissions

Blocked Self Only Unrestricted Not Set

accelerometer Blocked

ambient-light-sensor Blocked

autoplay Blocked

battery Blocked

bluetooth Blocked

browsing-topics Blocked

camera Blocked

ch-ua Blocked

clipboard-read Blocked

clipboard-write Blocked

conversion-measurement Blocked

display-capture Blocked

document-domain Blocked

document-write Blocked

encrypted-media Blocked

execution-while-not-rendered Blocked

execution-while-out-of-viewport Blocked

focus-without-user-activation Blocked

fullscreen Blocked

gamepad Blocked

geolocation Blocked

gyroscope Blocked

hid Blocked

idle-detection Blocked

interest-cohort Blocked

keyboard-map Blocked

local-fonts Blocked

magnetometer Blocked

microphone Blocked

midi Blocked

navigation-override Blocked

payment Blocked

picture-in-picture Blocked

publickey-credentials-get Blocked

screen-wake-lock Blocked

serial Blocked

speaker Blocked

speaker-selection Blocked

sync-xhr Blocked

trust-token-redemption Blocked

usb Blocked

wake-lock Blocked

webauthn Blocked

web-share Blocked

window-placement Blocked

vr Blocked

xr Blocked

xr-spatial-tracking Blocked

A+

security.txt

Signed, 2 contact(s) — RFC 9116 compliant

PASS

security.txt

Contact: mailto:team@f-droid.org, https://gitlab.com/fdroid/admin/issues

Encryption: https://keys.openpgp.org/vks/v1/by-fingerprint/EE6620C7136B0D2C456C0A4DE9E28DEA00AA5556, https://keys.openpgp.org/vks/v1/by-fingerprint/37D2C98789D8311948394E3E41E7044E1DBA2E89, https://keys.openpgp.org/vks/v1/by-fingerprint/3DBDBA23810AEE377CC8E9D7C84324635610899F

Policy: https://f-droid.org/.well-known/security.txt

A

Transport Security

HTTP/3, HSTS, and TLS version analysis

PASS

HTTP/3, HSTS, and TLS version analysis

HTTP/3 (QUIC) not advertised

HTTP/3 eliminates head-of-line blocking. If your CDN supports it, consider enabling it.

HSTS enabled (base policy)

HSTS missing includeSubDomains

Without includeSubDomains, HSTS only protects the exact domain.

TLS 1.3 in use (fastest handshake, 1-RTT)