CVE-2025-27893

Executive Summary

CVE-2025-27893 affects Archer Platform versions 6 through 6.14.00202.10024. The vulnerability allows an authenticated user with record creation privileges to manipulate immutable fields (e.g., creation date) by intercepting and modifying a Copy request via a GenericContent/Record.aspx?id= URI. However, the vendor analysis indicates that while the user can modify the field in edit mode, switching to View mode reverts the field to its original value, and no data is saved to the database. The CVSS score is 1.8 (Low), and the EPSS score is 0.0%, indicating minimal exploitation likelihood. No public exploit code or patch is available.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a web application vulnerability in the Archer Platform.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:N
• Base Score: 1.8 (Low)
• Attack Vector: Network (AV:N)
• Attack Complexity: High (AC:H) – requires intercepting and modifying a request
• Privileges Required: High (PR:H) – authenticated user with record creation privileges
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: None (C:N)
• Integrity Impact: None (I:N) – field reverts on view
• Availability Impact: None (A:N)

Threat Level: Low. The vulnerability has no real impact as the immutable field reverts upon viewing, and no data is persisted.

Deep Dive & Mechanics

The vulnerability lies in the GenericContent/Record.aspx page. When a user with record creation privileges copies a record, the application allows modification of immutable fields (e.g., creation date) via a crafted POST request. The application does not validate that these fields should remain unchanged during the copy operation. However, the vendor states that upon switching to View mode, the field reverts to its original value, and nothing is saved to the database. This suggests a client-side or session-based manipulation that does not persist.

Root Cause: Improper input validation (CWE-20) on the server side, allowing modification of fields that should be immutable. However, the lack of persistence reduces the impact to negligible.

Vulnerable vs. Patched Code

No patch is available. The vendor considers the behavior as non-impactful. The vulnerable code likely does not enforce immutability on the server side during the copy operation. A patched version would validate that immutable fields are not modified in the request.

Vulnerable Code (Conceptual):

// No validation of immutable fields
public void CopyRecord(int id, Dictionary<string, object> fields)
{
    // Directly updates fields without checking immutability
    UpdateRecord(id, fields);
}

Patched Code (Conceptual):

public void CopyRecord(int id, Dictionary<string, object> fields)
{
    // Remove immutable fields from the update
    fields.Remove("CreationDate");
    fields.Remove("CreatedBy");
    UpdateRecord(id, fields);
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• Authenticated user with record creation privileges
• Ability to intercept and modify HTTP requests (e.g., Burp Suite)

Steps:

1. Log in to Archer Platform.
2. Navigate to a record and select "Copy".
3. Intercept the POST request to GenericContent/Record.aspx?id=<record_id>.
4. Modify the CreationDate parameter to a desired value.
5. Forward the request.
6. Observe that the field appears modified in edit mode but reverts upon viewing.

Proof of Concept (PoC) Request:

POST /GenericContent/Record.aspx?id=123 HTTP/1.1
Host: target-archer.com
Content-Type: application/x-www-form-urlencoded

__VIEWSTATE=...&CreationDate=2025-01-01&...

Blue Team

Detection:

• Monitor for unusual modifications to immutable fields in copy requests.
• Alert on requests to GenericContent/Record.aspx with unexpected parameters.

Mitigation:

• Implement server-side validation to reject modifications to immutable fields.
• Restrict record creation privileges to trusted users.

Indicators of Compromise (IOCs)

• Network: HTTP POST requests to /GenericContent/Record.aspx with modified immutable fields (e.g., CreationDate).
• Logs: Audit logs showing changes to immutable fields that are later reverted.
• Endpoint: Unusual user activity involving copy operations on records.

Detection Engineering

YARA Rule

rule CVE_2025_27893_Archer_Immutable_Field_Manipulation
{
    meta:
        description = "Detects attempts to manipulate immutable fields in Archer Platform copy requests"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "CVE-2025-27893"
    strings:
        $s1 = "GenericContent/Record.aspx" nocase
        $s2 = "CreationDate" nocase
        $s3 = "CreatedBy" nocase
    condition:
        all of them
}

Sigma Rule

title: Archer Platform Immutable Field Manipulation Attempt
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects HTTP requests attempting to modify immutable fields in Archer Platform
author: Valters IT
date: 2025-04-01
logsource:
    category: webserver
    product: iis
detection:
    selection:
        cs-uri-query|contains: 'GenericContent/Record.aspx'
        cs-method: 'POST'
        cs-uri-query|contains|all:
            - 'CreationDate'
            - 'CreatedBy'
    condition: selection
falsepositives:
    - Legitimate copy operations (if any)
level: low

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-27893 Archer Platform Immutable Field Manipulation Attempt";
    flow:to_server,established;
    content:"POST";
    http_method;
    content:"GenericContent/Record.aspx";
    http_uri;
    content:"CreationDate";
    http_client_body;
    content:"CreatedBy";
    http_client_body;
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

• Restrict record creation privileges to only trusted users.
• Implement server-side validation to reject modifications to immutable fields.

Long-term Fix:

• Apply vendor patch when available (currently none).
• Upgrade to a patched version of Archer Platform.

Workarounds:

• Monitor logs for unusual copy operations.
• Use Web Application Firewall (WAF) rules to block requests with modified immutable fields.

Valters IT
DevSecOps & Cyber Threat Intelligence