Security Reboot Required

Kernel updates without KernelCare do usually require rebooting. But the update version's change log or official site's version release announcement would mention it. And usually some common and crucial library updates which other software has dependencies would require restarts i.e. openssh, openssl system package, glibc, libssh2

i.e.

• libssh2 Security - Security Vulnerabilitys for libssh2 (CVE-2016-0787) & libssh (CVE-2016-0739)
• glibc Security - glibc vulnerability CVE-2015-7547
• glibc again Security - CVE-2015-0235 glibc heap-based buffer overflow (Ghost Vulnerability)

Sometimes reboot isn't required just restarting the service(s) which has dependencies on the updated libraries i.e. openssl would usually relate to sshd services and nginx and php too. Can use lsof command to list open files 10 lsof Command Examples in Linux

or ldd to find libraries used by binaries i.e. nginx binary's libraries

Code (Text):

ldd $(which nginx)
        linux-vdso.so.1 =>  (0x00007ffeed927000)
        librt.so.1 => /lib64/librt.so.1 (0x00007f04a98c4000)
        libjemalloc.so.1 => /lib64/libjemalloc.so.1 (0x00007f04a968f000)
        libdl.so.2 => /lib64/libdl.so.2 (0x00007f04a948b000)
        libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f04a926f000)
        libcrypt.so.1 => /lib64/libcrypt.so.1 (0x00007f04a9037000)
        libGeoIP.so.1 => /lib64/libGeoIP.so.1 (0x00007f04a8e05000)
        libc.so.6 => /lib64/libc.so.6 (0x00007f04a8a44000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f04a9adc000)
        libfreebl3.so => /lib64/libfreebl3.so (0x00007f04a8840000)

i.e. for libcrypt.so.1 for glibc-devel RPM package

Code (Text):

yum provides *lib64/libcrypt.so.1 -q
glibc-2.17-157.el7.x86_64 : The GNU libc libraries
Repo        : base
Matched from:
Filename    : /lib64/libcrypt.so.1

glibc-2.17-157.el7_3.1.x86_64 : The GNU libc libraries
Repo        : updates
Matched from:
Filename    : /lib64/libcrypt.so.1

glibc-2.17-157.el7_3.2.x86_64 : The GNU libc libraries
Repo        : updates
Matched from:
Filename    : /lib64/libcrypt.so.1

glibc-2.17-157.el7_3.4.x86_64 : The GNU libc libraries
Repo        : updates
Matched from:
Filename    : /lib64/libcrypt.so.1

glibc-2.17-157.el7_3.4.x86_64 : The GNU libc libraries
Repo        : @updates
Matched from:
Filename    : /lib64/libcrypt.so.1

for /lib64/libfreebl3.so for nss-softokn-freebl-3 RPM package

Code (Text):

yum provides */lib64/libfreebl3.so -q
nss-softokn-freebl-3.16.2.3-14.4.el7.x86_64 : Freebl library for the Network Security Services
Repo        : base
Matched from:
Filename    : /usr/lib64/libfreebl3.so

nss-softokn-freebl-3.16.2.3-14.4.el7.x86_64 : Freebl library for the Network Security Services
Repo        : @anaconda
Matched from:
Filename    : /usr/lib64/libfreebl3.so

Yes that does mean alot of reading