Advantech Webaccess

Multiple stack-based buffer overflows in Advantech WebAccess before 7.2 allow remote attackers to execute arbitrary code via a long string in the (1) ProjectName, (2) SetParameter, (3) NodeName, (4) CCDParameter, (5) SetColor, (6) AlarmImage, (7) GetParameter, (8) GetColor, (9) ServerResponse, (10) SetBaud, or (11) IPAddress parameter to an ActiveX control in (a) webvact.ocx, (b) dvs.ocx, or (c) webdact.ocx.Show less

The BWOCXRUN.BwocxrunCtrl.1 control contains a method named “CreateProcess.” This method contains validation to ensure an attacker cannot run arbitrary command lines. After validation, the values supplied in the HTML are passed to the Windows CreateProcessA API. The validation can be bypassed allowing for running arbitrary command lines. The command line can specify running remote files (example: UNC command line). A function exists at offset 100019B0 of bwocxrun.ocx. Inside this function, there are 3 calls to strstr to check the contents of the user specified command line. If “\setup.exe,” “\bwvbprt.exe,” or “\bwvbprtl.exe” are contained in the command line (strstr returns nonzero value), the command line passes validation and is then passed to CreateProcessA.Show less

The BWOCXRUN.BwocxrunCtrl.1 control contains a method named OpenUrlToBufferTimeout. This method takes a URL as a parameter and returns its contents to the caller in JavaScript. The URLs are accessed in the security context of the current browser session. The control does not perform any URL validation and allows file:// URLs that access the local disk. The method can be used to open a URL (including file URLs) and read the URLs through JavaScript. This method could also be used to reach any arbitrary URL to which the browser has access.Show less

The BWOCXRUN.BwocxrunCtrl.1 control contains a method named “OpenUrlToBuffer.” This method takes a URL as a parameter and returns its contents to the caller in JavaScript. The URLs are accessed in the security context of the current browser session. The control does not perform any URL validation and allows “file://” URLs that access the local disk. The method can be used to open a URL (including file URLs) and read file URLs through JavaScript. This method could also be used to reach any arbitrary URL to which the browser has access.Show less

An attacker may exploit this vulnerability by passing an overly long value from the AccessCode argument to the control. This will overflow the static stack buffer. The attacker may then execute code on the target device remotely.Show less

An attacker can exploit this vulnerability by copying an overly long NodeName2 argument into a statically sized buffer on the stack to overflow the static stack buffer. An attacker may use this vulnerability to remotely execute arbitrary code.Show less