By John Leyden
Published Tuesday 8th February 2005 13:58 GMT
Forensic computing techniques proved decisive in proving staff at a Buckinghamshire primary school had not been surfing for porn at work. The head of the school called in Disklabs, a computer forensics and data firm, last year when he discovered web folders with pornographic content on a PC used by pupils. The history of these folders suggested a creation date during lesson time and a modified date on a teacher-training day.
Opinion was divided among County ICT staff and the head teachers' union as to whether the images and bookmarks had been made intentionally or if this was due to a malicious program. Faced with the potential risk to pupils, the need to treat staff fairly and responsibilities to the school and its governors, Staffordshire-based Disklabs was asked to conduct an independent forensic analysis of the suspect PC.
The analysis showed definitively that the presence of suspect content was caused by a program from the well-known spy and adware family, Istbar Adware. The program downloaded content to infected PCs without users' knowledge or agreement. Disklabs' analysis report cleared the school, staff and pupils of any doubt, and gave vital independent corroboration of the school's position without exposing it to the negative publicity a police inquiry might generate.
CSI for PCs
Like a conventional crime scene, PCs contain evidence and an audit trail of user activity. After isolating the system to preserve evidence, Disklabs used specialised forensic tools to search hidden folders and unallocated disk space, verifying exactly how the files arrived and whether this was down to human intent or a malicious program. Findings are delivered in a complete procedural report.
Disklabs has seen demand for its forensics services grow by over 70 per cent in the last year, driven by the boom in spyware. Many organisations, especially in the public sector, are turning to computer forensics to establish if misuse or an infection is to blame for inappropriate material found on computers. Some types of Spyware and particular viruses are capable of changing users' internet favourites and bookmarks, downloading images to hard disks and stealing information on user activities from infected PCs.
Recent research by technology US ISP Earthlink and anti-spyware firm Webroot revealed that Windows PCS harbour 25 separate, malicious programs on average. The audit surveyed over 4.6 million PCs last year, finding more than 116.5m instances of spyware, Trojans and other malicious programs. Incidents of Trojans – the worst category of infection – in PCs submitted to Webroot’s SpyAudit rose from 130,322 in Q1 2004 to 769,330 in Q4 2004.
Disklabs director Simon Steggles said: "With so many malicious programs on the web, organisations are realising that PCs with inappropriate images or content may not have been misused by individuals, but unwittingly infected. Forensics can establish beyond doubt whether this is the case, and also presents evidence which can be used to support the chosen course of action." ®
