CVE-2024-38176: Microsoft GroupMe Privilege Escalation

CVE-2024-38176 Overview

CVE-2024-38176 is an elevation of privilege vulnerability in Microsoft GroupMe. The flaw stems from improper restriction of excessive authentication attempts [CWE-307]. An unauthenticated attacker can abuse this weakness over a network to elevate privileges within the GroupMe service. Microsoft published the advisory on July 23, 2024, and the issue is tracked in the Microsoft Security Update Guide.

The vulnerability carries a CVSS 3.1 base score of 8.1 and affects confidentiality, integrity, and availability. No public proof-of-concept exploit is available, and the CVE is not listed in the CISA Known Exploited Vulnerabilities catalog.

Critical Impact
An unauthenticated network attacker can elevate privileges in Microsoft GroupMe by abusing missing rate limiting on authentication attempts.

Affected Products

Microsoft GroupMe (service)
Component identifier: microsoft:groupme
CPE: cpe:2.3:a:microsoft:groupme:-:*:*:*:*:*:*:*

Discovery Timeline

2024-07-23 - CVE-2024-38176 published to NVD
2024-07-23 - Microsoft Security Update Guide advisory released
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-38176

Vulnerability Analysis

The vulnerability is categorized as Improper Restriction of Excessive Authentication Attempts [CWE-307]. GroupMe's authentication flow does not adequately throttle or lock out repeated authentication requests from the same source. This weakness enables high-volume credential testing against accounts exposed through the service.

Successful exploitation grants the attacker access to a victim account, which Microsoft classifies as an elevation of privilege outcome. The attack requires no prior authentication and no user interaction. Attack complexity is rated High, indicating that the attacker must overcome conditions beyond simple submission, such as specific timing or evasion of partial defenses.

Root Cause

The root cause is missing or insufficient enforcement of authentication attempt limits. Effective controls in this class include account lockout thresholds, exponential backoff, IP-based throttling, and CAPTCHA challenges after a defined number of failures. The absence of one or more of these controls in GroupMe's authentication path enabled brute-force or credential-stuffing attacks to succeed.

Attack Vector

The attack vector is network-based. An attacker sends repeated authentication requests to the GroupMe service against a targeted user or set of users. Without effective rate limiting, the attacker iterates through candidate passwords until a valid credential is found. Once authenticated, the attacker assumes the privileges of the compromised account, including access to private messages, groups, and contacts.

No exploitation code is publicly available. The vulnerability mechanism is described in prose because no verified proof-of-concept has been published. Refer to the Microsoft Security Update Guide for vendor technical details.

Detection Methods for CVE-2024-38176

Indicators of Compromise

High volumes of failed authentication events for a single GroupMe account from one or more source addresses.
Successful GroupMe logins from geolocations, devices, or IP ranges inconsistent with the account's historical pattern.
New device registrations or session tokens issued shortly after a burst of failed authentication attempts.
Outbound activity from compromised accounts including mass messaging, group creation, or contact enumeration.

Detection Strategies

Correlate authentication telemetry from Microsoft Entra ID and GroupMe sign-in logs to identify brute-force and credential-stuffing patterns.
Alert on impossible travel and atypical sign-in properties for accounts that also use GroupMe.
Hunt for distributed low-and-slow password spraying that bypasses per-IP thresholds.

Monitoring Recommendations

Forward GroupMe and Microsoft identity sign-in logs to a centralized SIEM for retention and correlation.
Track failed-to-successful authentication ratios per account and per source IP over rolling windows.
Monitor for password reset and MFA enrollment changes that follow suspicious authentication bursts.

How to Mitigate CVE-2024-38176

Immediate Actions Required

Confirm the Microsoft service-side fix is in effect by reviewing the Microsoft Security Update Guide entry for CVE-2024-38176.
Force password resets for GroupMe accounts that show signs of brute-force targeting or anomalous sign-in activity.
Enable and enforce multi-factor authentication on Microsoft accounts used with GroupMe.
Review session and device lists for affected accounts and revoke unrecognized sessions.

Patch Information

CVE-2024-38176 affects a Microsoft-operated service. Microsoft remediated the issue on the service side, and no customer-deployed patch is required. Validate the fix and obtain authoritative remediation guidance from the Microsoft Security Update Guide.

Workarounds

Enforce strong, unique passwords for GroupMe accounts to reduce success rates of credential stuffing.
Require MFA for the underlying Microsoft account to block privilege elevation even if a password is guessed.
Restrict account recovery options to verified channels and disable legacy authentication where feasible.
Educate users to report unexpected sign-in notifications and lockout messages promptly.

bash

# Example: query Microsoft sign-in logs for repeated failures followed by success
# (run in Microsoft Graph / Azure CLI with appropriate permissions)
az rest --method GET \
  --uri "https://graph.microsoft.com/v1.0/auditLogs/signIns?\$filter=status/errorCode ne 0" \
  --query "value[].{user:userPrincipalName,ip:ipAddress,app:appDisplayName,err:status.errorCode,time:createdDateTime}"