用 Codex 或 Claude 帮你安装 复制这段 Prompt，粘贴到 Codex、Claude 或其他助手里，让它检查 Skill 页面并帮你完成安装。
直接命令不会经过审查 Prompt；运行前请先检查来源。
npx skills add https://github.com/CyberStrikeus/CyberStrike --skill cis-ubuntu2004-v300-3-3-10命令会保持在同一行。复制前请横向滚动并检查完整内容。
想先保存到本地？可下载 SkillsMP 当前能够提供的文件。
macOS post-exploitation for credential harvesting, DTrace monitoring, TCC bypass, and stealth operations via native tools
Windows userland post-exploitation for credential harvesting, monitoring, AMSI/ETW bypass, and stealth operations
Kubernetes post-exploitation for container escape, secret extraction, RBAC abuse, and cluster persistence
基于 SOC 职业分类
正在显示 SKILL.md
| name | cis-ubuntu2004-v300-3-3-10 |
| description | Ensure tcp syn cookies is enabled |
| category | cis-networking |
| version | 3.0.0 |
| author | cyberstrike-official |
| tags | ["cis","ubuntu","linux","ubuntu-20.04","kernel-parameter"] |
| cis_id | 3.3.10 |
| cis_benchmark | CIS Ubuntu Linux 20.04 LTS Benchmark v3.0.0 |
| tech_stack | ["ubuntu","linux"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
When tcp_syncookies is set, the kernel will handle TCP SYN packets normally until the half-open connection queue is full, at which time, the SYN cookie functionality kicks in. SYN cookies work by not using the SYN queue at all. Instead, the kernel simply replies to the SYN with a SYN/ACK, but will include a specially crafted TCP sequence number that encodes the source and destination IP address and port number and the time the packet was sent. A legitimate connection would send the ACK packet of the three way handshake with the specially crafted sequence number. This allows the system to verify that it has received a valid response to a SYN cookie and allow the connection, even though there is no corresponding SYN in the queue.
Attackers use SYN flood attacks to perform a denial of service attacked on a system by sending many SYN packets without completing the three way handshake. This will quickly use up slots in the kernel's half-open connection queue and prevent legitimate connections from succeeding. Setting net.ipv4.tcp_syncookies to 1 enables SYN cookies, allowing the system to keep accepting valid connections, even if under a denial of service attack.
None expected.
Run the following script to verify the following kernel parameter is set in the running configuration and correctly loaded from a kernel parameter configuration file:
net.ipv4.tcp_syncookies is set to 1Note: kernel parameters are loaded by file and parameter order precedence. The following script observes this precedence as part of the auditing procedure. The parameters being checked may be set correctly in a file. If that file is superseded, the parameter is overridden by an incorrect setting later in that file, or in a canonically later file, that "correct" setting will be ignored both by the script and by the system during a normal kernel parameter load sequence.
Audit Result: ** PASS ** with net.ipv4.tcp_syncookies set to 1.
Set the following parameter in /etc/sysctl.conf or a file in /etc/sysctl.d/ ending in .conf:
net.ipv4.tcp_syncookies = 1Example:
# printf '%s\n' "net.ipv4.tcp_syncookies = 1" >> /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.tcp_syncookies=1
sysctl -w net.ipv4.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.tcp_syncookies = 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 |