eBay hacking: Can a shill bidder discover a legit bidder's max bid amount?

I had an eBay auction experience this morning that really raised my eyebrows.

Minutes before an auction was about to end the top bid was about $17. I knew this was grossly under the real value of the item so when I submitted my bid – about 60 secs before the end – I entered my true maximum bid amount, $42.50. This made me the leading bidder at around $18 – but only for a few moments.

Just seconds before the auction ended someone else slipped in a bid – one only pennies less than my $42.50. I still won the auction, but instead of paying the $18, I paid the $42.50.

Now I know that there are shill bidders – third party false bidders who work on behalf of the seller to boost the bids of legit buyers. I’ve always assumed they worked on a trial and error process: the shill ups the bid in increments in the hope that he can get as close to a legit bidder’s maximum without actually winning the auction. But has some hacker devised a way to discover another bidder’s max bid so he can shill right up to the edge of that max in one grand jump – what seemingly happened to me?

Of course, my experience this morning could be just a pure coincidence. After all, the alleged shill has a long history of clean eBay buying and selling. I just want to know if I have any reason to be suspicious.

You can search on a bidder’s history in eBay (you go to Advanced Search, then Search by Bidder. Look at the person’s recent bidding history on completed auctions to see if there is a pattern. As you say, this one time might be a coincidence.

You were ‘sniped’. You can have a company bid for you in the last few seconds of the auction. This usually occurs much faster than the human can bid, hit enter, re-bid again if too low. The program just keeps increasing the bid until your max is reached or you win. Simliar to proxy bidding, only you don’t tip your hand or push the amount up.

www.esnipe.com is one such company.

No, I wasn’t sniped. The object of sniping is to win the auction. The object of shilling is to **let the other guy win the auction ** – for the maximum he is willing to pay. Reread my original post and you’ll see the distinction.

Dude, take it down a notch. You still could’ve been sniped, only he didn’t bid enough…i.e I tell esnipe to bid up to $42.48 a nice odd number. It bids, your proxy is $42.50. Time runs out, you were still sniped. I just didn’t win.

That is nothing like how it works.

What you are suggesting is no different to what ebay’s proxy bidding would do for you anyway. All you are gaining from a sniping company is someone else (or their software) is doing the sniping for you. But it’s no different from sitting in front of your own computer at the right time and entering, once and once only, your max bid at the last moment.

Continually incrementing and submitting is doing things the hard way to absolutely no advantage.

As to the OP; sounds like a coincidence. And in your case a lucky coincidence. You nearly lost it. I suspect that the other bidder has conspiracy theories of their own just now. How did you know to up your bid by just enough at the last minute to beat them?

Ebay at least assures buyers that no-one knows your max bid.

Holmes, my apologies if I came off snippy (snipey?) – entirely not my intent, I assure you.

I realize that I was sniped, if by that you mean he posted a bid in the closing seconds. But to say someone has been sniped usually implies that they lost the auction; I did not. Furthermore, his bid does not show the signs of autosniping – there were no rapidfire incremental bids at the last second. There was just one big last-second bid that came shy of mine by mere pennies.

Again, I apologize if you took the tone of my previous post the wrong way.

Except the other bidder placed their bid after the OP. No conspiracy, just the vagaries of proxy bidding.

I think that if someone figured out how to hack through ebay’s security that the millions of credit card numebrs on file would be of more value to them than raising the price on auctions they run.

Not necessarily. There is no reason to assume that the two things are systemically related. (Indeed, if there are competent people working at eBay, they shouled not be.) It is conceivable that a person could discover a security flaw allowing him access to bid information, while still not having any particular access to credit card info.

That unlikely hypothetical aside, I vote for eerie coincidence.

To the OP, I say coincidence.

To credit cards vs. secret bidding info (reserves, high bids), I’d take knowing secret bidding information. Credit card nos by themselves aren’t much good. You need safe houses for delivery or other information to use them for most illicit uses and its a risk everytime. Quietly reading secret bidding information can safely get you stuff for cheap.

The psychology behind auctions can be complex. A big benefit to the seller is that the bidders get one another into a frenzy. I wonder how many people who, after they submit their proxy bid that is the highest they are willing to pay for an item, will increase their bid after they find out someone else is willing to bid more.

The other side of the coin is that if you keep your bid low, but snipe at the last second, the price you are willing to pay may be higher than that of others, but you don’t want to tip your hand too early, inciting others to also raise their maximum bid (see previous paragraph).

I would say that OP was sniped but the sniper just didn’t go quite high enough.

I am a relative eBay novice, but a quick question:

What if another bidder came in with 5 seconds left in the auction and bid exactly $42.50? Would the OP still win the auction having to pay $42.50? Or would the auction go to some kind of tie break auction? He was not outbid so I don’t know the exact rules – the OP would seem to have precedence from simply have entered that bid before the other bidder. Since $42.50 was both of their top bets, is it possible that a bug/feature of the eBay system is that the second bidder could not enter a $42.50 top bet and instead, since another bidder had precedence, it assigned second bidder to $42.48 and with a $0.02 bid increment then the OP won at $42.50?

Just wondering, you know.

edwino:

Yes, the first guy would win. In order to outbid someone, you need not only to go higher than the existing top bid, but you need to top it by a certain amount. A tie certainly would go to the first bidder.

Actually, I think the ebay software would not accept the second guy’s bid at all. That’s what I recall happening when I entered a bid at the same time (actually, must have been a few seconds later) as someone else, and for the same amount. The ebay system told me that my bid had to be x amount over the current winning bid, and would not accept it.

Are you positive? Because I was pretty sure that the high bid always wins, even if tops the previous bid by less than the increment amount.

I was waiting to see if an expert on schill bidding posted, but it doesn’t look like it, so I’m gonna go ahead and post my personal theory as to how this might have happened. I think there are certain “round” amounts for every auction where people think, “That’s about the most I would pay for that.” Maybe $40 just sort of seemed like the “right amount” for that item. Now most savvy eBayers will bid an odd amount, like $41.55 or whatever, in case it ends up in a tie. That way, if someone else bids $40, they still win. Like the OP, I usually go $2 and change over that “round” amount in order to beat the guys who are going $1 or $2 over the round amount. So maybe that’s what happened. The other guy thought, "I’ll bid a little over 40 bucks, and came in just under the OP, who bid just a little more over 40 bucks.

But I’ve definitely had that same feeling before, where you win by just a few cents, and it almost seems like too much of a coincidence.

Re: discovering your high bid
Sure, anyone can do it – they just can’t do it very often without risking getting caught. When the bid is $18.00, they can simply bid $1850(.00). Due to eBay’s proxy bidding system, they will be the hign bidder at just over your highest competing bid (e.g. 45.00) Then they can retract the bid, saying that they left out the decimal point. Lame, yes, but I’m sure enough people genuinely mistype without noticing that it’ll seem plausible to eBay - if they don’t do it very often (There’s an eBay policy on bid retration, but the last time I saw it, it wasn’t very specific on the threshold. I suspect it depends on how many people lodge a complaint about you retracting, and how energetic the employee handling each new complaint is feeling.)

If a bid is retracted, the high bid should go back to what it was before. I’ve seen a few cases where it didn’t seem to, but that was years ago, and I assume that bug was fixed. It didn’t go back down due to a quirk of eBay proxy bidding: you couldn’t just raise your existing proxy bid, you could only enter a higher proxy bid that competed with your earlier proxy bid (a bad idea in most cases).

If the bidding returns to the pre-retraction state as it should, a retracted ludicrous bid would discover your high bid, and could bid just under it (e.g. $44.99) forcing you to your highest approved proxy bid. It is actually expected that you will place a “real” bid after you retract; not doing so makes your retracted bid look suspicious.

In the few auctions where I’ve seen retrations (I’ve never actually retracted a bid myself), it seemed to be a manual practice that required eBay intervention, and probably takes more time to process. However, if you weren’t watching the auction “live” but came back an hour later, after the retraction was processed, the “bid history” transcript might have been “fixed” as part of the manual resolution process, and you might be looking at what looks like a miraculous guess

Or the bid history might show the retration. It depends on how their CSR’s "retraction screen is currently set up, and how diligent the CSR is about policy.

However, it is still more likely that the other bidder’s estimation of the item’s value was very close to yours. In that case, one of you will edge the other out by a hair.

RE: bidding increments
Though you can only outbid the CURRENT high bid by the minimum bid increment, you can outbid the FINAL bid by less, if you set your maximum proxy bid to an irregular amount, or if some other bidder does.

e.g. if the current bid is $50.00, you can’t bid $50.01, but if you set your proxy to $50.01 when the current bid was $45, you’ll beat someone who bid $50. Also if there was a bidder whose LOSING maximum was 48.01, all subsequent bids will increment from that maximum (i.e. 47.00 … 47.50 … 48.00 … 48.01 … 48.51 …).

You might expect the “high bid” to leapfrog over the irregular amount, since your next minimum bid is higher than it anyway, but if you think about it, the most computationally efficient method to match two proxy bids is to compare them once, and se the high bid accordingly, rather than enact the step-by-step incrementation – that made even more sense with the slower, less powerful servers of the 90s, but it still sensible with today’s servers, since millions of bids are made every day, and most of the heavy action is in the final minute or so.

Probably quite a few. Bidding would be so much easier if people didn’t get emotionally involved with the process and just bid what they were prepared to pay.

The only advantage to sniping is that it gives other bidders less time to talk themselves into upping their bid beyond what they first decided. If everyone just bid their absolute maximum in the first place there would be absolutely no point to it.

But I guess this is why ebay works the way it does, the sellers rely on the buyers getting carried away by other’s bids to increase the selling price. Otherwise the sensible way of conducting the auction would be to make it completely blind. No-one sees what anyone else has bid, everyone bids their max, no-one knows who’s won until the end, the selling price is a fraction over the top of the second highest bid. Thus there would be no point or way to snipe.

The only advantage I can see to putting in a low bid, and then upping it in a last minute snipe, is that if you forget the auction end date, or miss it, there’s still a slight chance you might get a bargain at your initially low bid. Otherwise you’re as well completely sitting out the bidding until the last minute.

This is possible, but it is easy to confirm if it happened in this case. Go to the auction and click on the number of bids to access the bid history. Any bid retractions will be listed there.

Yeah, but one of the appeals of the auction system is that it also accurately conveys price information. I may not know what a 1965 Beanie Babie with a slightly frayed cuff might be worth, but everyone else bidding gives me a reasonable idea.

Personally, I think the way to stop sniping would be to adopt the amazon style system where an auction closes only when its past X date and there has not been a bid for Y minutes. It’s impossible to snipe since every bid keeps the auction going.