Collaborate Disseminate
Are there any security reasons against "drop-www"?
In other words, are there any security reasons against using an apex [1] domain name such as example.com instead of a subdomain such as www.example.com?
Quote https://www.bjornjo… Continue reading Are there any security reasons against "drop-www" (using example.com instead of www.example.com)?
Many people have written about DKIM header injection attacks. [1] The suggestion to mitigate it is to oversign headers and to rotate any DKIM keys that were previously used to sign e-mails where not all important headers have been oversign… Continue reading How many times need e-mail headers be signed with DKIM to mitigate DKIM header injection attacks?
Quote https://manpages.debian.org/buster/manpages/ld.so.8.en.html#Secure-execution_mode
Secure-execution mode
For security reasons, the effects of some environment variables are voided or modified if the dynamic linker determines that the… Continue reading How to globally enable ld.so secure-execution mode for all applications?
If a webapp sends Cache-Control: private it shouldn’t be cached for example with nginx proxy_cache. What could happen if it was cached anyhow? Could another visitor see the personalized login of another user? Might another visitor then bei… Continue reading Can server-side caching misconfiguration lead to stolen logins?
Is there any reason to show a Content-Security-Policy (CSP) HTTP Header for direct links to images such as https://invalid.tld/direct-link-to-image.jpeg?
Continue reading Content-Security-Policy (CSP) HTTP Header useful for direct link to image?
Why hide kernel symbols?
Quote
Anyone with basic knowledge of kernel exploitation knows how important information gathering is to reliable exploitation. This protection hides the kernel symbols from various places that an attacker cou… Continue reading How to hide Kernel Symbols in Linux Kernel Image? Recompliation?
How to create an OpenVPN static / pre-shared key with key size 4096 or 8192 bit?
openvpn –genkey
Creates 2048 bit strong keys only.
Static key. Not CA.
Continue reading How to generate an OpenVPN 4096 or 8192 bit static key?
Suppose a non-root user was compromised over remote by malware that is now using su (tty or similar) trying to login as root, trying every possible password by bruteforcing.
assume: full disk encryption with a strong passsword is in place… Continue reading How strong do linux user account passwords have to be when using Full Disk Encryption (FDE) too?
Example systemd unit file, what I mean by “seccomp”.
ProtectSystem=full
ProtectHome=true
ProtectKernelTunables=true
ProtectKernelModules=true
ProtectControlGroups=true
PrivateTmp=true
PrivateMounts=true
PrivateDevices=true
MemoryDenyWrite… Continue reading Is it possible to use systemd seccomp filtering for running applications from command line?
Usually there’s just one e-mail / e-mail password / domain registrar username / password. And perhaps one 2FA (google authenticator) device and a 2FA recovery code.
Either an employee has access to these credentials or not. … Continue reading How to secure a domain name from insider threats, domain hijacking in a corperate context?