Shadow Brokers, the mysterious group that gained international renown when it published hundreds of advanced hacking tools belonging to the National Security Agency, says it's going dark. But before it does, it's lobbing a Molotov cocktail that's sure to further inflame the US intelligence community.

In a farewell message posted Thursday morning, group members said they were deleting their accounts and making an exit after their offers to release their entire cache of NSA hacking tools in exchange for a whopping 10,000 bitcoins (currently valued at more than $8.2 million) were rebuffed. While they said they would still make good on the offer should the sum be transferred into their electronic wallet, they said there would be no more communications.

"Despite theories, it always being about bitcoins for TheShadowBrokers," Thursday's post, which wasn't available as this article was going live, stated. "Free dumps and bullshit political talk was being for marketing attention. There being no bitcoins in free dumps and giveaways. You are being disappointed? Nobody is being more disappointed than TheShadowBrokers."

Parting insult

The post included 61 Windows-formatted binary files, including executables, dynamic link libraries, and device drivers. While, according to this analysis , 43 of them were detected by antivirus products from Kaspersky Lab, which in 2015 published a detailed technical expose into the NSA-tied Equation Group only one of them had previously been uploaded to the Virus Total malware scanning service. And even then, Virus Total showed that the sample was detected by only 32 of 58 AV products even though it had been uploaded to the service in 2009. After being loaded into Virus Total on Thursday, a second file included in the farewell post was detected by only 12 of the 58 products.

Malware experts are still analyzing the files, but early indications are that, as was the case with earlier Shadow Brokers dumps, they belonged to the Tailored Access Operations, the NSA's elite hacking unit responsible for breaking into the computers and networks of US adversaries. And given evidence the files remained undetected by many of the world's most widely used malware defenses, Thursday's farewell message may have been little more than a parting insult, particularly if the group has origins in the Russian government, as members of the intelligence community have speculated.

"This farewell message is kind of a burn-it-to-the-ground moment," Jake Williams, a malware expert and founder of Rendition Infosec, told Ars. "Russian ties make sense given the inauguration [of Donald Trump] happens in a short time [from now]. If that narrative is correct and Shadow Brokers is Russian, they wouldn't be able to release those tools after Trump takes office. If you roll with that narrative, [the burn-it-to-the-ground theory] certainly works."

Under such theories, Russian hackers attempted to sway the 2016 presidential election in favor of Trump in hopes his policies would be more favorable to Russia than Hillary Clinton's. Once Trump takes office, Russian hackers would want to prevent any blowback from hitting the new president. Thursday's farewell message came within hours of a new dispatch from Guccifer 2.0, the online persona that leaked hacked Democratic e-mails that the US intelligence community said was a front for Russian operatives. In the post, Guccifer 2.0 strenuously rejected the accusation that he was Russian and claimed evidence to the contrary was false.

Thursday's dump came several days after Shadow Brokers members published screenshots of what they claimed were NSA-developed exploits for Windows systems. While the absence of the actual files themselves made analysis impossible, the screenshots and the file names suggested the cache may have included a backdoor made possible by a currently unpatched vulnerability in the Windows implementation of the Server Message Block protocol.

Other tools appeared to provide:

bypasses for antivirus programs from at least a dozen providers, including Kaspersky, Symantec, McAfee, and Trend Micro

a streamlined way to surgically remove entries from event logs used to forensically investigate breached computers and networks

hacks for a Windows-based e-mail client known as WorldTouch

capabilities for gaining administrator privileges or dumping passwords on Window machines.

A Kaspersky Lab representative issued the following statement:

"At Kaspersky Lab, we have checked a copy of the archive from the latest Shadow Brokers post and performed a quick analysis. Most of the samples in the archive are EquationDrug plugins, GrayFish modules and EquationVector modules. These three are known malware platforms used by the Equation group, which we described in February 2015. From the list of 61 files provided, our products already detect 44 of them. We are updating our products to detect all further samples.

The full text of the Shadow Broker's farewell post read:

So long, farewell peoples. TheShadowBrokers is going dark, making exit. Continuing is being much risk and bullshit, not many bitcoins. TheShadowBrokers is deleting accounts and moving on so don’t be trying communications. Despite theories, it always being about bitcoins for TheShadowBrokers. Free dumps and bullshit political talk was being for marketing attention. There being no bitcoins in free dumps and giveaways. You are being disappointed? Nobody is being more disappointed than TheShadowBrokers. But TheShadowBrokers is leaving door open. You having TheShadowBrokers public bitcoin address 19BY2XCgbDe6WtTVbTyzM9eR3LYr6VitWK TheShadowBrokers offer is still being good, no expiration. If TheShadowBrokers receiving 10,000 btc in bitcoin address then coming out of hiding and dumping password for Linux + Windows. Before go, TheShadowBrokers dropped Equation Group Windows Warez onto system with Kaspersky security product. 58 files popped Kaspersky alert for equationdrug.generic and equationdrug.k TheShadowBrokers is giving you popped files and including corresponding LP files. Password is FuckTheWorld Is being final fuck you, you should have been believing TheShadowBrokers.

Files included with the post carried the following names:

DoubleFeatureDll.dll.unfinalized

DuplicateToken_Implant.dll

DuplicateToken_Lp.dll

DXGHLP16.SYS

EventLogEdit_Implant.dll

EventLogEdit_Lp.dll

GetAdmin_Implant.dll

GetAdmin_Lp.dll

kill_Implant9x.dll

kill_Implant.dll

LSADUMP_Implant.dll

LSADUMP_Lp.dll

modifyAudit_Implant.dll

modifyAudit_Lp.dll

modifyAuthentication_Implant.dll

modifyAuthentication_Lp.dll

ModifyGroup_Implant.dll

ModifyGroup_Lp.dll

ModifyPrivilege_Implant.dll

ModifyPrivilege_Lp.dll

msgkd.ex_

msgki.ex_

msgks.ex_

msgku.ex_

mssld.dll

msslu.dll

mstcp32.sys

nethide_Implant.dll

nethide_Lp.dll

ntevt.sys

ntevtx64.sys

ntfltmgr.sys

PassFreely_Implant.dll

PassFreely_Lp.dll

PC_Legacy_dll

PC_Level3_dll

PC_Level3_dll_x64

PC_Level3_flav_dll

PC_Level3_flav_dll_x64

PC_Level3_http_dll

PC_Level3_http_dll_x64

PC_Level3_http_flav_dll

PC_Level3_http_flav_dll_x64

PC_Level4_flav_dll

PC_Level4_flav_dll_x64

PC_Level4_flav_exe

PC_Level4_http_flav_dll

PC_Level4_http_flav_dll_x64

PortMap_Implant.dll

PortMap_Lp.dll

ProcessHide_Implant.dll

ProcessHide_Lp.dll

processinfo_Implant9x.dll

processinfo_Implant.dll

ProcessOptions_Implant.dll

ProcessOptions_Lp.dll

pwdump_Implant.dll

pwdump_Lp.dll

RunAsChild_Implant.dll

RunAsChild_Lp.dll

tdi6.sys

Of interest to researchers looking for clues about the people behind Shadow Brokers, Images included with the file dump showed the files were included on a Drive D that was most likely a USB drive, given an accompanying icon. The folder was titled DSZOPSDISK, a string that also matches a folder name from a previous exploit dump. The evidence "lends credibility to the argument the leak came from an insider who stole, and subsequently lost control of, a USB stick, rather than a direct hack of the NSA," independent researcher Matt Tait, who posts under the Twitter handle Pwn All The Things, told Ars. As Tait also observed, the computer the drive was attached to appeared to be running Kaspersky AV and VMware tools, had no connected network or sound card, and was configured to show dates in the dd/mm/yyyy format. The files were signed by the same cryptographic key used to sign previous Shadow Broker dumps.

Tracking bear prints

Thursday's post comes five months after Shadow Brokers first appeared. A day after the unprecedented leak, Kaspersky Lab researchers definitively tied the included exploits to the NSA-connected Equation Group . A day after that, Cisco Systems confirmed that the leaked cache included a zero-day exploit that had secretly targeted one of its firewall products for years . In October, Shadow Brokers published a document r evealing hundreds of networks that were targeted by the NSA over more than a decade.

One theory floated by intelligence officers and reported by The New York Times is that the Shadow Brokers leaks were carried out by Russian operatives as a warning to the US not to publicly escalate blame of President Vladimir Putin for hacks on the Democratic National Committee. NSA leaker Edward Snowden and a host of others have also speculated that Russia is behind the Shadow Brokers as well. There's no definitive proof of Russian involvement, but the timing of Thursday's farewell and the potentially damaging leaks that accompanied it—coming eight days before the inauguration of President-elect Donald Trump—give the unescapable impression of a link.

"They may not be Russian," Williams said of the Shadow Brokers members. "But it is inexplicable they would release the dump without understanding the timing and how it would be read. Anyone smart enough to steal these tools understands the conclusion that will be drawn by most."