Egress Connection by a YUM Package Manager Descendant


Description

Detects suspicious network events executed by the Yum package manager, potentially indicating persistence through a Yum backdoor. In Linux, Yum (Yellowdog Updater, Modified) is a command-line utility used for handling packages on Fedora-based systems, providing functions for installing, updating, upgrading, and removing software along with managing package repositories. Attackers can backdoor Yum to gain persistence by injecting malicious code into plugins that Yum runs, thereby ensuring continued unauthorized access or control each time Yum is used for package management. For this persistence mechanism to work, plugins need to be enabled in the /etc/dnf/dnf.conf and plugin.conf files.

Query · eql

sequence by process.entity_id with maxspan=5s
  [process where event.type == "start" and event.action == "exec" and (
   process.name : (
     "bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish", "python*", "php*",
     "perl", "ruby", "lua*", "openssl", "nc", "ncat", "netcat", "netcat.openbsd",
     "netcat.traditional", "nc.openbsd", "nc.traditional", "telnet", "awk"
   ) or
   process.executable : (
     "./*", "/boot/*", "/dev/shm/*", "/etc/cron.*/*", "/etc/init.d/*", "/etc/update-motd.d/*", "/run/*", "/srv/*",
     "/tmp/*", "/var/tmp/*", "/var/log/*"
     )
   ) and descendant of [process where event.action == "exec" and process.name == "yum"] and not (
     process.executable : "/run/user/*/newroot/*" or
     process.args : "/usr/local/cpanel/*"
   )
  ]
  [network where event.action == "connection_attempted" and event.type == "start" and not (
     destination.ip == null or destination.ip == "0.0.0.0" or cidrmatch(
       destination.ip, "10.0.0.0/8", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12", "192.0.0.0/24", "192.0.0.0/29",
       "192.0.0.8/32", "192.0.0.9/32", "192.0.0.10/32", "192.0.0.170/32", "192.0.0.171/32", "192.0.2.0/24",
       "192.31.196.0/24", "192.52.193.0/24", "192.168.0.0/16", "192.88.99.0/24", "224.0.0.0/4", "100.64.0.0/10",
       "192.175.48.0/24","198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "240.0.0.0/4", "::1", "FE80::/10",
       "FF00::/8", "172.31.0.0/16"
       ) or
     process.name in ("yumBackend.py", "urlgrabber-ext-down") or
     process.executable in ("/usr/share/logstash/jdk/bin/java", "/opt/java/openjdk/bin/java", "/usr/local/cpanel/scripts/rebuildhttpdconf")
     )
  ]
Raw source Egress Connection by a YUM Package Manager Descendant · Elastic TOML
Esc
Published by elastic/protections-artifacts ↗, licensed under Elastic License 2.0 ↗. Reproduced here unmodified.
[rule]
description = """
Detects suspicious network events executed by the Yum package manager, potentially indicating persistence through a Yum
backdoor. In Linux, Yum (Yellowdog Updater, Modified) is a command-line utility used for handling packages on
Fedora-based systems, providing functions for installing, updating, upgrading, and removing software along with managing
package repositories. Attackers can backdoor Yum to gain persistence by injecting malicious code into plugins that Yum
runs, thereby ensuring continued unauthorized access or control each time Yum is used for package management. For this
persistence mechanism to work, plugins need to be enabled in the `/etc/dnf/dnf.conf` and plugin.conf files.
"""
id = "74afd5bc-7d44-4a11-9383-a5e30c3ec8ae"
license = "Elastic License v2"
name = "Egress Connection by a YUM Package Manager Descendant"
os_list = ["linux"]
reference = [
    "https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/local/yum_package_manager_persistence.rb",
    "https://www.elastic.co/security-labs/sequel-on-persistence-mechanisms",
]
version = "1.0.8"

query = '''
sequence by process.entity_id with maxspan=5s
  [process where event.type == "start" and event.action == "exec" and (
   process.name : (
     "bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish", "python*", "php*",
     "perl", "ruby", "lua*", "openssl", "nc", "ncat", "netcat", "netcat.openbsd",
     "netcat.traditional", "nc.openbsd", "nc.traditional", "telnet", "awk"
   ) or
   process.executable : (
     "./*", "/boot/*", "/dev/shm/*", "/etc/cron.*/*", "/etc/init.d/*", "/etc/update-motd.d/*", "/run/*", "/srv/*",
     "/tmp/*", "/var/tmp/*", "/var/log/*"
     )
   ) and descendant of [process where event.action == "exec" and process.name == "yum"] and not (
     process.executable : "/run/user/*/newroot/*" or
     process.args : "/usr/local/cpanel/*"
   )
  ]
  [network where event.action == "connection_attempted" and event.type == "start" and not (
     destination.ip == null or destination.ip == "0.0.0.0" or cidrmatch(
       destination.ip, "10.0.0.0/8", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12", "192.0.0.0/24", "192.0.0.0/29",
       "192.0.0.8/32", "192.0.0.9/32", "192.0.0.10/32", "192.0.0.170/32", "192.0.0.171/32", "192.0.2.0/24",
       "192.31.196.0/24", "192.52.193.0/24", "192.168.0.0/16", "192.88.99.0/24", "224.0.0.0/4", "100.64.0.0/10",
       "192.175.48.0/24","198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "240.0.0.0/4", "::1", "FE80::/10",
       "FF00::/8", "172.31.0.0/16"
       ) or
     process.name in ("yumBackend.py", "urlgrabber-ext-down") or
     process.executable in ("/usr/share/logstash/jdk/bin/java", "/opt/java/openjdk/bin/java", "/usr/local/cpanel/scripts/rebuildhttpdconf")
     )
  ]
'''

min_endpoint_version = "7.15.0"
optional_actions = []
[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 1

[[threat]]
framework = "MITRE ATT&CK"
[[threat.technique]]
id = "T1543"
name = "Create or Modify System Process"
reference = "https://attack.mitre.org/techniques/T1543/"

[[threat.technique]]
id = "T1574"
name = "Hijack Execution Flow"
reference = "https://attack.mitre.org/techniques/T1574/"


[threat.tactic]
id = "TA0003"
name = "Persistence"
reference = "https://attack.mitre.org/tactics/TA0003/"
[[threat]]
framework = "MITRE ATT&CK"

[threat.tactic]
id = "TA0005"
name = "Defense Evasion"
reference = "https://attack.mitre.org/tactics/TA0005/"
[[threat]]
framework = "MITRE ATT&CK"

[threat.tactic]
id = "TA0011"
name = "Command and Control"
reference = "https://attack.mitre.org/tactics/TA0011/"

[internal]
min_endpoint_version = "7.15.0"

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