Impact: Moderate Public Date: 2019-02-06 CWE: CWE-121 Bugzilla: 1670254: CVE-2019-3822 curl: NTLMv2 type-3 header stack buffer overflow libcurl versions from 7.36.0 to before 7.64.0 are vulnerable to a stack-based buffer overflow. The function creating an outgoing NTLM type-3 header (`lib/vauth/ntlm.c:Curl_auth_create_ntlm_type3_message()`), generates the request HTTP header contents based on previously received data. The check that exists to prevent the local buffer from getting overflowed is implemented wrongly (using unsigned math) and as such it does not prevent the overflow from happening. This output data can grow larger than the local buffer if very large 'nt response' data is extracted from a previous NTLMv2 header provided by the malicious or broken HTTP server. Such a 'large value' needs to be around 1000 bytes or more. The actual payload data copied to the target buffer comes from the NTLMv2 type-2 response header.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2019-3822 from the MITRE CVE dictionary dictionary and NIST NVD.
The versions of curl package shipped with Red Hat Enterprise Linux 5, 6 and 7 do not support NTLMv2 type-3 headers, hence they are not affected by this flaw.
NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.
| CVSS3 Base Score | 5.3 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H |
| Attack Vector | Network |
| Attack Complexity | High |
| Privileges Required | None |
| User Interaction | Required |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity Impact | None |
| Availability Impact | High |
| Platform | Package | State |
|---|---|---|
| Red Hat Virtualization 4 | curl | Under investigation |
| Red Hat Software Collections for Red Hat Enterprise Linux | httpd24-curl | Affected |
| Red Hat JBoss Web Server 5 | curl | Under investigation |
| Red Hat JBoss Core Services 1 | curl | Under investigation |
| Red Hat Enterprise Linux 7 | curl | Not affected |
| Red Hat Enterprise Linux 6 | curl | Not affected |
| Red Hat Enterprise Linux 5 | curl | Not affected |
| .NET Core 2.0 on Red Hat Enterprise Linux | rh-dotnet22-curl | Under investigation |
| .NET Core 2.0 on Red Hat Enterprise Linux | rh-dotnet21-curl | Under investigation |
| .NET Core 1.0 on Red Hat Enterprise Linux | rh-dotnetcore10-curl | Under investigation |
| .NET Core 1.0 on Red Hat Enterprise Linux | rh-dotnetcore11-curl | Under investigation |
Turn off NTLM authentication.
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