XL-2020-004 - Asset Explorer (Windows & Linux) - Authenticated Command Execution
===============================================================================
Identifiers
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* CVE-2019-19034
* XL-20-004
CVSSv3 score
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7.2 (AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H)
Vendor
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ManageEngine - [https://www.manageengine.com/products/asset-explorer/](https://www.manageengine.com/products/asset-explorer/)
Product
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ManageEngine AssetExplorer is a web-based IT Asset Management (ITAM) software that helps you monitor and manage assets in your network from Planning phase to Disposal phase. AssetExplorer provides you with a number of ways to ensure discovery of all the assets in your network. You can manage software & hardware assets, ensure software license compliance and track purchase orders & contracts - the whole nine yards! AssetExplorer is very easy to install and works right out of the box.
Affected versions
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- All versions prior to 6.5 (6503)
Credit
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Sahil Dhar - xen1thLabs - Software Labs
Vulnerability summary
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ManageEngine Asset Explorer application does not validate System Center Configuration Manager (SCCM) database username when dynamically generating a command to schedule scans for SCCM. The vulnerability allows an attacker to execute arbitrary commands on the AssetExplorer Server with NT AUTHORITY/SYSTEM privileges.
Technical details
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The username is concatenated to the system command on line `143` and `144` of `SccmTask.java` from `AdventNetAsset.jar` package, before being executed through the `exec()` method from `java.lang.Runtime` class on line `147` or `149`.
The following code snippet displays the vulnerable souce code:
```java
/*
Package Name: AdventNetAsset.jar
FileName: SccmTask.java
*/
123: prop.setProperty("hostName", sccmHostName);
124: prop.setProperty("databaseName", sccmDbName);
125: prop.setProperty("domain", "-".equals(sccmDomain) ? "" : sccmDomain);
126: prop.setProperty("username", sccmUserName);
127: prop.setProperty("port", sccmPortNum);
128: prop.setProperty("password", Encoder.convertFromBase(sccmPassword));
129:
130: DBConnectorUtil connectionTester = new DBConnectorUtil(prop, false);
131:
132: HashMap<String, Object> auditStart = new HashMap();
133: auditStart.put("sccmId", sccmConfigId);
134: auditStart.put("sccmName", sccmName);
135: auditStart.put("startTime", new Timestamp(startTime.longValue()));
136: auditStart.put("auditToken", auditId);
137: SCCMUtil.updateSCCMScanStartAudit(auditStart);
138:
140: if (connectionTester.testConnection())
141: {
142: logger.log(Level.INFO, "Connection has been established with the required SCCM");
143: String runSccmWindows = "SCCMScheduler.bat " + sccmDomain + " " + sccmPortNum + " " + sccmDbName + " " + sccmHostName + " " + sccmUserName + " " + sccmPassword + " " + sccmConfigId.toString() + " " + auditId + " " + siteId + " " + auditURL;
144: String runSccmLinux = "sh SCCMScheduler.sh " + sccmDomain + " " + sccmPortNum + " " + sccmDbName + " " + sccmHostName + " " + sccmUserName + " " + sccmPassword + " " + sccmConfigId.toString() + " " + auditId + " " + siteId + " " + auditURL;
145: if (System.getProperty("os.name").indexOf("Windows") != -1)
146: {
147: Runtime.getRuntime().exec(runSccmWindows);
148: } else {
149: Runtime.getRuntime().exec(runSccmLinux);
150: }
151: logger.log(Level.INFO, "SCCM Scanner is lauched. Log file is created in directory: ROOT/logs/SCCMLogs/");
152: }
```
Proof of concept
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1. Set `| calc.exe &` as a username of one of the databases of the SCCM database server.
2. Authenticate to the application with Administrator credentials and navigate to Admin > Discovery > Crdential Library.
3. Add one SCCM credential with authentication mode as SQL and username as `| calc.exe &` and password for SCCM database server.
4. Navigate to SCCM integration, fill in the required parameters and select the credentials added in `step 3` and schedule a scan.
5. Observe that the application executes `calc.exe` with NT AUTHORITY/SYSTEM privileges.
Solution
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This issue is fixed in ManageEngine AssetExplorer 6.6 version.
Timeline
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15-09-2019 - Reported to vendor
17-09-2019 - Vendor acknowledgement
21-11-2019 - Patch released
13-05-2020 - xen1thLabs public disclosure
