CVE-2024-1708 - ScreenConnect Path Traversal Exploitation - Security

Status: test
Severity: critical
Log source: product windows, service security
Author: Matt Anderson, Caleb Stewart, Huntress
Source: github.com/SigmaHQ/sigma

This detects file modifications to ASPX and ASHX files within the root of the App_Extensions directory, which is allowed by a ZipSlip vulnerability in versions prior to 23.9.8. This occurs during exploitation of CVE-2024-1708. This requires an Advanced Auditing policy to log a successful Windows Event ID 4663 events and with a SACL set on the directory.

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	No specific technique
Persistence	No specific technique

Event coverage

Provider	Event	Title
Security-Auditing	Event ID 4663	An attempt was made to access an object.

Rule body yaml

title: CVE-2024-1708 - ScreenConnect Path Traversal Exploitation - Security
id: 4c198a60-7d05-4daf-8bf7-4136fb6f5c62
related:
    - id: 44d7af7e-88e6-4490-be11-55f7ff4d9fc1
      type: similar
status: test
description: |
    This detects file modifications to ASPX and ASHX files within the root of the App_Extensions directory, which is allowed by a ZipSlip vulnerability in versions prior to 23.9.8. This occurs during exploitation of CVE-2024-1708.
    This requires an Advanced Auditing policy to log a successful Windows Event ID 4663 events and with a SACL set on the directory.
references:
    - https://www.connectwise.com/company/trust/security-bulletins/connectwise-screenconnect-23.9.8
    - https://www.cve.org/CVERecord?id=CVE-2024-1708
    - https://www.huntress.com/blog/a-catastrophe-for-control-understanding-the-screenconnect-authentication-bypass
author: Matt Anderson, Caleb Stewart, Huntress
date: 2024-02-20
tags:
    - attack.initial-access
    - attack.persistence
    - cve.2024-1708
    - detection.emerging-threats
logsource:
    product: windows
    service: security
    definition: 'Requirements: SACLs must be enabled for the ScreenConnect directory'
detection:
    selection:
        EventID: 4663
        ObjectType: 'File'
        ProcessName|contains: 'ScreenConnect.Service.exe'
        AccessMask: '0x6'
        ObjectName|endswith:
            - 'ScreenConnect\\App_Extensions\\*.ashx'
            - 'ScreenConnect\\App_Extensions\\*.aspx'
    filter_main_legit_extension:
        ObjectName|contains: 'ScreenConnect\App_Extensions\\*\\'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unknown
level: critical

Stages and Predicates

Stage 0: `condition`

selection and not 1 of filter_main_*

Stage 1: `selection`

selection:
    EventID: 4663
    ObjectType: 'File'
    ProcessName|contains: 'ScreenConnect.Service.exe'
    AccessMask: '0x6'
    ObjectName|endswith:
        - 'ScreenConnect\\App_Extensions\\*.ashx'
        - 'ScreenConnect\\App_Extensions\\*.aspx'

Stage 2: `not filter_main_legit_extension`

filter_main_legit_extension:
    ObjectName|contains: 'ScreenConnect\App_Extensions\\*\\'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`ObjectName`	match	`ScreenConnect\App_Extensions\\*\\`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`AccessMask`	eq	`0x6` corpus 3 (sigma 2, kusto 1)
`ObjectName`	ends_with	`ScreenConnect\\App_Extensions\\.ashx` `ScreenConnect\\App_Extensions\\.aspx`
`ObjectType`	eq	`File` corpus 10 (sigma 8, splunk 2)
`ProcessName`	match	`ScreenConnect.Service.exe` corpus 2 (sigma 2)

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

CVE-2024-1708 - ScreenConnect Path Traversal Exploitation - Security

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection`

Stage 2: `not filter_main_legit_extension`

Exclusions

Indicators

Keyboard shortcuts

Search operators

CVE-2024-1708 - ScreenConnect Path Traversal Exploitation - Security

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection

Stage 2: not filter_main_legit_extension

Exclusions

Indicators

Stage 0: `condition`

Stage 1: `selection`

Stage 2: `not filter_main_legit_extension`