back door

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back door

(Or "trap door", "wormhole"). A hole in the security of a system deliberately left in place by designers or maintainers. The motivation for such holes is not always sinister; some operating systems, for example, come out of the box with privileged accounts intended for use by field service technicians or the vendor's maintenance programmers. See also iron box, cracker, worm, logic bomb.

Historically, back doors have often lurked in systems longer than anyone expected or planned, and a few have become widely known. The infamous RTM worm of late 1988, for example, used a back door in the BSD Unix "sendmail(8)" utility.

Ken Thompson's 1983 Turing Award lecture to the ACM revealed the existence of a back door in early Unix versions that may have qualified as the most fiendishly clever security hack of all time. The C compiler contained code that would recognise when the "login" command was being recompiled and insert some code recognizing a password chosen by Thompson, giving him entry to the system whether or not an account had been created for him.

Normally such a back door could be removed by removing it from the source code for the compiler and recompiling the compiler. But to recompile the compiler, you have to *use* the compiler - so Thompson also arranged that the compiler would *recognise when it was compiling a version of itself*, and insert into the recompiled compiler the code to insert into the recompiled "login" the code to allow Thompson entry - and, of course, the code to recognise itself and do the whole thing again the next time around! And having done this once, he was then able to recompile the compiler from the original sources; the hack perpetuated itself invisibly, leaving the back door in place and active but with no trace in the sources.

The talk that revealed this truly moby hack was published as ["Reflections on Trusting Trust", "Communications of the ACM 27", 8 (August 1984), pp. 761--763].

back door

A secret way to take control of a computer. Also called "trap doors," back doors are built into software by the original programmer, who can gain access to the computer by entering a code locally or remotely. For example, a back door in an application would enable a person to activate either normal or hidden functions within the software. A back door in an operating system would provide access to all system functions in the computer. See Easter Egg and Back Orifice.
References in periodicals archive ?
The backdoor is perceived as an area of risk in the retailer's mind as they are trying to tighten security.
According to a statement from Vodafone, the backdoors were eventually addressed though it did not provide any firm dates.
In his letter to the Philippine Stock Exchange sent through his lawyers, dated January 11, Okada said the ownership of all his companies, including that of the local company that operates Okada Manila, should be settled first before any backdoor listing could occur.
It is publicly known that the Mokes backdoor (also known as "Smoke Bot" or "Smoke Loader") appeared on Russian underground forums as it was made available for purchase in 2011.
Manzoor quoted Zardari as saying that Finance Minister Ishaq Dar was destroying the country since he had no knowledge about the economy.Party leader Nadeem Afzal Chan told the reporters that the ousted prime minister Nawaz Sharif's strategy to establish backdoor contacts was nothing but the last effort to "save his own skin and money".
Regretfully, the Build release of our full line of products on July 18th, 2017 was unknowingly shipped with a backdoor which had the potential to be exploited by its creator.
Let's say the bank had tied a ribbon round the disk drive and said, "Don't make me cut this ribbon because you'll make me cut it many times." The article includes a quote from FBI director James Comey in support of forcing Apple to provide a backdoor to the iOS platform.
In early 2015, the attackers used Backdoor.Breut to mainly target Indian organizations.
backdoor known as SHOTPUT, detected by FireEye as Backdoor.APT.CookieCutter,
Skilful Champ, narrowly beaten by Shutthe Backdoor in the Red Mills Champion Unraced at Kilkenny, was the star performer in the first round of the Red Mills Champion Juvenile on the undercard.
Tahirul Qadri has started making efforts through backdoor channels to end January 14 long march to save prestige after opposition from major political and religious parties.