Cisco NVM - Installation of Typosquatted Python Package

SPLUNK detection rule by Nasreddine Bencherchali, Splunk · Apache-2.0

This analytic detects suspicious python package installations where the package name resembles popular Python libraries but may be typosquatted or slightly altered. Typosquatting is a common technique used by attackers to trick users into installing malicious packages that mimic legitimate ones. This detection leverages Cisco NVM flow telemetry and checks for pip or poetry package managers with the "install" or "add" flags, making outbound connections to package repository such as `pypi.org` with known or suspected typo package names.

name: Cisco NVM - Installation of Typosquatted Python Package
id: 5e3f6b44-42cb-4f8a-99f0-59e78a52ea1d
version: 5
creation_date: '2025-07-01'
modification_date: '2026-07-14'
author: Nasreddine Bencherchali, Splunk
status: production
type: TTP
description: |
    This analytic detects suspicious python package installations where the package name resembles popular Python libraries but may be typosquatted or slightly altered.
    Typosquatting is a common technique used by attackers to trick users into installing malicious packages that mimic legitimate ones.
    This detection leverages Cisco NVM flow telemetry and checks for pip or poetry package managers with the "install" or "add" flags, making outbound connections to package repository such as `pypi.org` with known or suspected typo package names.
data_source:
    - Cisco Network Visibility Module Flow Data
search: |
    `cisco_network_visibility_module_flowdata`
    dest_hostname IN ("*.pythonhosted.org", "*pypi.org", "*python-poetry.org")
    (
      (process_arguments = "*pip*" process_arguments = "*install*")
      OR
      (process_arguments = "*poetry*" process_arguments = "*add*")
    )
    | rex field=process_arguments "(?i)(?:pip|poetry)[^|]*?\s+(?:install|add)\s+(?P<package_name>[^\s\"']+)$"
    | lookup typo_squatted_python_packages
             typosquatted_package_name as package_name
             OUTPUTNEW comment package_official_url
    | where isnotnull(comment)
    | stats count min(_time) as firstTime max(_time) as lastTime
            values(parent_process_arguments) as parent_process_arguments
            values(process_arguments) as process_arguments
            values(parent_process_hash) as parent_process_hash
            values(process_hash) as process_hash
            values(module_name_list) as module_name_list
            values(module_hash_list) as module_hash_list
            values(dest_port) as dest_port
            values(aliul) as additional_logged_in_users_list
            values(dest_hostname) as dest_hostname
            by src dest parent_process_path parent_process_integrity_level process_path process_name process_integrity_level process_id transport package_name comment package_official_url
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | table firstTime lastTime src dest_hostname dest dest_port transport  package_name comment package_official_url
      parent_process_integrity_level parent_process_path parent_process_arguments parent_process_hash
      process_integrity_level process_path process_name process_arguments process_hash process_id
      additional_logged_in_users_list module_name_list module_hash_list
    | `cisco_nvm___installation_of_typosquatted_python_package_filter`
how_to_implement: |
    This search requires Network Visibility Module logs, which includes the flow data sourcetype.
    This search uses an input macro named `cisco_network_visibility_module_flowdata`.
    We strongly recommend that you specify your environment-specific configurations
    (index, source, sourcetype, etc.) for Cisco Network Visibility Module logs.
    Replace the macro definition with configurations for your Splunk environment.
    The search also uses a post-filter macro designed to filter out known false positives.
    The logs are to be ingested using the Splunk Add-on for Cisco Endpoint Security Analytics (CESA) (https://splunkbase.splunk.com/app/4221).
    In addition to this, the search make use of the lookup "typo_squatted_python_packages". Which needs to be configured and tuned.
known_false_positives: |
    False positives should be very minimal to non existent, as the names of the packages in the lookup are all extracted from previously malicious packages.
references:
    - https://securelist.com/two-more-malicious-python-packages-in-the-pypi/107218/
    - https://blog.checkpoint.com/securing-the-cloud/pypi-inundated-by-malicious-typosquatting-campaign/
    - https://rhisac.org/threat-intelligence/typosquatting-campaign-targets-python-developers-with-hundreds-of-malicious-libraries/
drilldown_searches:
    - name: View the detection results for - "$src$"
      search: '%original_detection_search% | search  src = "$src$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$src$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$src$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: Host $src$ used pip or poetry to install a likely typosquatted python package $package_name$ from $dest_hostname$
    entity:
        field: src
        type: system
        score: 50
threat_objects:
    - field: process_name
      type: process_name
analytic_story:
    - Cisco Network Visibility Module Analytics
asset_type: Endpoint
mitre_attack_id:
    - T1059
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test - Cisco NVM
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/cisco_network_visibility_module/cisco_nvm_flowdata/nvm_flowdata.log
          source: not_applicable
          sourcetype: cisco:nvm:flowdata:v2
      test_type: unit

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

90906f74-89d8-4fc2-8f18-1e9e299479c4

Propose edits, view related rules, and engage with the community through comments.

Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

Community Discussion