Shortcut: Ctrl+F (when in hex edit mode)
Hex find provides basic find functionality while in hex edit mode. The search will always begin at the caret location (rather than from top of file).
The hex find dialog includes the following options:
Find what
Enter the hex values to search in this field. Hex strings should have two characters per byte and each byte can optionally be separated with a space, for example "48 65 78" or "486578".
This field also includes a search history, accessible by clicking the down arrow to open the drop down.
Find ASCII
Check this option to search for a regular plain text string while in hex edit mode, just as you would while in plain text mode. If this option is set, only the ASCII representation column on the right is searched, and any matches are selected there.
Regular expressions (ASCII only)
Check this option to use UltraEdit-style regular expressions in the find string. This option will only work if Find ASCII is enabled.
Direction
When set to down, this will search forward from the current caret position to the next match. When set to up, this will search backward from the current caret position to the previous match.
UltraEdit Wiki