Secure attention key
A secure attention key (SAK), special attention key,[1] or secure attention sequence (SAS)[2] is a special key, key combination or sequence to be pressed on a computer keyboard before a login screen which must, to the user, be completely trustworthy. The operating system kernel, which interacts directly with the hardware, or init system is able to detect whether the secure attention key has been pressed. When this event is detected, the trusted login processing is started.
The secure attention key is designed to make login spoofing impossible, as the kernel will suspend any program, including those masquerading as the computer's login process, before starting a trustable login operation.
Examples
[edit ]Some examples are:
- Ctrl+Alt+⇧ Shift+Esc: Introduced in systemd v257 as a more reliable SAK for Linux distributions but may require support from the currently running desktop environment.[3] It is implemented as of gdm (GNOME display manager) 47.[4]
- Ctrl+Alt+← Backspace on X Window System immediately kills the X server (although the key combination can be disabled[5] ) and can be used to quickly and easily get back to the login prompt.[6]
- Alt+SysRq+K default sequence for Linux.[7] Not a true C2-compliant SAK.[8]
- Ctrl+X then Ctrl+R on AIX,[9] but it can be disabled.[10] [11]
- ⇧ Shift+Stop for PLATO IV in the 1970s.[12]
- Ctrl+Alt+Delete for Windows NT.[2] [13]
See also
[edit ]References
[edit ]- ^ Lennart Poettering (2024年11月07日). "Lennart Poettterin on Mastodon" . Retrieved 2025年03月26日.
- ^ a b Microsoft (7 January 2021). "S (Security Glossary) - Win32 apps | Microsoft Learn" . Retrieved 2023年04月02日.
- ^ Lennart Poettering (2024年11月07日). "Lennart Poettterin on Mastodon" . Retrieved 2025年03月26日.
- ^ Ray Strode (2024年09月11日). "47.rc" . Retrieved 2025年03月26日.
- ^ dhcp198-158 (2010年06月12日). "XorgCtrlAltBackspace" . Retrieved 2025年03月26日.
{{cite web}}: CS1 maint: numeric names: authors list (link) - ^ "Enabling the Ctrl+Alt+Backspace Shortcut" . Retrieved 2025年03月26日.
- ^ Andrew Morton (2001年03月18日). "Linux 2.4.2 Secure Attention Key (SAK) handling". Linux Kernel Organization. Retrieved 2011年05月30日.
- ^ "Linux Magic System Request Key Hacks". kernel.org. 2013年08月12日. Retrieved 2017年05月21日.
- ^ IBM (2025年02月03日). "Using the Secure Attention Key". IBM . Retrieved 2025年03月26日.
- ^ IBM (2025年02月03日). "Configuring the Secure Attention Key". IBM . Retrieved 2025年03月26日.
- ^ IBM (2025年02月20日). "AIX Default Attributes". IBM . Retrieved 2025年03月26日.
- ^ Control Data Corporation (1981年04月30日). "PLATO User's Guide" (PDF). Retrieved 2023年04月21日.
- ^ "Secure Attention Sequence (SAS) - Network Encyclopedia". 6 January 2020. Retrieved 2023年04月02日.
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