CVE-2021-20110
Due to Manage Engine Asset Explorer Agent 1.0.34 not validating HTTPS certificates, an attacker on the network can statically configure their IP address to match the Asset Explorer's Server IP address.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (7.38%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Due to Manage Engine Asset Explorer Agent 1.0.34 not validating HTTPS certificates, an attacker on the network can statically configure their IP address to match the Asset Explorer's Server IP address. This will allow an attacker to send a NEWSCAN request to a listening agent on the network as well as receive the agent's HTTP request verifying its authtoken. In httphandler.cpp, the agent reaching out over HTTP is vulnerable to an Integer Overflow, which can be turned into a Heap Overflow allowing for remote code execution as NT AUTHORITY/SYSTEM on the agent machine. The Integer Overflow occurs when receiving POST response from the Manage Engine server, and the agent calling "HttpQueryInfoW" in order to get the "Content-Length" size from the incoming POST request. This size is taken, but multiplied to a larger amount. If an attacker specifies a Content-Length size of 1073741823 or larger, this integer arithmetic will wrap the value back around to smaller integer, then calls "calloc" with this size to allocate memory. The following API "InternetReadFile" will copy the POST data into this buffer, which will be too small for the contents, and cause heap overflow.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 7.38% probability · 94th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-190
- Affected
- zohocorp/manageengine assetexplorer
- Source
- vulnreport@tenable.com
References
- https://www.tenable.com/security/research/tra-2021-31Third Party Advisory
- https://www.tenable.com/security/research/tra-2021-31Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.