Detection rules › Splunk
Windows RDP Bitmap Cache File Creation
This detection identifies the creation of Remote Desktop Protocol (RDP) bitmap cache files on a Windows system, typically located in the user’s profile under the Terminal Server Client cache directory. These files (.bmc, cache.bin) are generated when a user initiates an RDP session using the built-in mstsc.exe client. Their presence can indicate interactive remote access activity and may be useful in detecting lateral movement or unauthorized RDP usage. Monitoring this behavior is especially important, as attackers may attempt to delete or suppress these artifacts to evade forensic analysis.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Lateral Movement | T1021.001 Remote Services: Remote Desktop Protocol |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 11 | FileCreate |
Stages and Predicates
Stage 1: tstats
tstats WHERE Filesystem.file_path IN ("*\\Terminal Server Client\\Cache\\*.bmc", "*\\Terminal Server Client\\Cache\\cache*.bin") BY Filesystem.action, Filesystem.dest, Filesystem.file_access_time, Filesystem.file_create_time, Filesystem.file_hash, Filesystem.file_modify_time, Filesystem.file_name, Filesystem.file_path, Filesystem.file_acl, Filesystem.file_size, Filesystem.process_guid, Filesystem.process_id, Filesystem.user, Filesystem.vendor_product
Stage 2: search
search
Stage 3: search
search
Stage 4: search
search
Stage 5: search
search `macro`
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
Filesystem.file_path | in |
|