Vulnerability title: Denial Of Service In Sophos Anti Virus
|Affected Version:||10.0.11/Engine 3.48.x|
|Fixed Version:||10.0.11/Engine 3.50|
|Reported by:||Graham Sutherland|
The following system objects do not have access control lists (ACLs) set, thus allowing any user to access and manipulate them:
Global objects (in namespace \Global, a.k.a. \BaseNamedObjects): $$!_EVENT_$!__ $$!_EVENT_$!__DataUpdateRequest $$!_EVENT_$!__MmfMutexSAV-**** $$!_EVENT_$!__MmfMutexSAV-Info $$!_EVENT_$!__ReadyForUpdateSAV-**** $$!_EVENT_$!__ReadyForUpdateSAV-Info $$!_EVENT_$!__SAV-**** $$!_EVENT_$!__SAV-Info $$!_EVENT_$!__StateChange $$!_EVENT_$!__SuspendedSAV-**** $$!_EVENT_$!__SuspendedSAV-Info $$!_EVENT_$!__UpdateComplete $$!_EVENT_$!__UpdateMutex $$!_EVENT_$!__UpdateRequest $$!_MMMF_$!__ SAV-**** SAV-Info Session objects (in namespace \Sessions\n\BaseNamedObjects): SophosALMonSessionInstance
By manipulating these objects, we found that we could cause the following problems:
Local denial of service by setting a locked or fired state on all mutexes and events. Machine becomes sluggish, certain features stop working, OS locks up and eventually BSoDs. We suspect that this is caused by an object wait call (e.g. WaitForSingleObject) in a kernel thread.
False display of “ready for update” message popup by repeatedly triggering the ReadyForUpdateSAV events and UpdateComplete / UpdateMutex / UpdateRequest objects.
The proof of concept exploit code is available.
|23/11/2013||Vendor working on a fix|
|21/01/2014||Fix released (Engine v 3.50)|
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