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macOS post-exploitation for credential harvesting, DTrace monitoring, TCC bypass, and stealth operations via native tools
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Showing SKILL.md
| name | cis-ubuntu2004-v300-3-3-5 |
| description | Ensure icmp redirects are not accepted |
| category | cis-networking |
| version | 3.0.0 |
| author | cyberstrike-official |
| tags | ["cis","ubuntu","linux","ubuntu-20.04","kernel-parameter"] |
| cis_id | 3.3.5 |
| cis_benchmark | CIS Ubuntu Linux 20.04 LTS Benchmark v3.0.0 |
| tech_stack | ["ubuntu","linux"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
ICMP redirect messages are packets that convey routing information and tell your host (acting as a router) to send packets via an alternate path. It is a way of allowing an outside routing device to update your system routing tables.
ICMP redirect messages are packets that convey routing information and tell your host (acting as a router) to send packets via an alternate path. It is a way of allowing an outside routing device to update your system routing tables. By setting net.ipv4.conf.all.accept_redirects, net.ipv4.conf.default.accept_redirects, net.ipv6.conf.all.accept_redirects, and net.ipv6.conf.default.accept_redirects to 0, the system will not accept any ICMP redirect messages, and therefore, won't allow outsiders to update the system's routing tables.
None expected.
Run the following script to verify the following kernel parameters are set in the running configuration and correctly loaded from a kernel parameter configuration file:
net.ipv4.conf.all.accept_redirects is set to 0net.ipv4.conf.default.accept_redirects is set to 0net.ipv6.conf.all.accept_redirects is set to 0net.ipv6.conf.default.accept_redirects is set to 0Note:
Audit Result: ** PASS ** with all four accept_redirects parameters set to 0 (or IPv6 parameters not applicable if IPv6 is disabled).
Set the following parameters in /etc/sysctl.conf or a file in /etc/sysctl.d/ ending in .conf:
net.ipv4.conf.all.accept_redirects = 0net.ipv4.conf.default.accept_redirects = 0Example:
# printf '%s\n' "net.ipv4.conf.all.accept_redirects = 0" "net.ipv4.conf.default.accept_redirects = 0" >>
/etc/sysctl.d/60-netipv4_sysctl.conf
Run the following script to set the active kernel parameters:
#!/usr/bin/env bash
{
sysctl -w net.ipv4.conf.all.accept_redirects=0
sysctl -w net.ipv4.conf.default.accept_redirects=0
sysctl -w net.ipv4.route.flush=1
}
IF - IPv6 is enabled on the system:
Set the following parameters in /etc/sysctl.conf or a file in /etc/sysctl.d/ ending in .conf:
net.ipv6.conf.all.accept_redirects = 0
net.ipv6.conf.default.accept_redirects = 0
Example:
# printf '%s\n' "net.ipv6.conf.all.accept_redirects = 0" "net.ipv6.conf.default.accept_redirects = 0" >>
/etc/sysctl.d/60-netipv6_sysctl.conf
Run the following script to set the active kernel parameters:
#!/usr/bin/env bash
{
sysctl -w net.ipv6.conf.all.accept_redirects=0
sysctl -w net.ipv6.conf.default.accept_redirects=0
sysctl -w net.ipv6.route.flush=1
}
Note: If these settings appear in a canonically later file, or later in the same file, these settings will be overwritten.
net.ipv4.conf.all.accept_redirects = 1
net.ipv4.conf.default.accept_redirects = 1
net.ipv6.conf.all.accept_redirects = 1
net.ipv6.conf.default.accept_redirects = 1
| Controls Version | Control | IG 1 | IG 2 | IG 3 |
|---|---|---|---|---|
| v8 | 4.8 Uninstall or Disable Unnecessary Services on Enterprise Assets and Software | x | x | |
| v7 | 9.2 Ensure Only Approved Ports, Protocols and Services Are Running | x | x |