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CCleaner Attack Timeline—Here’s How Hackers Infected 2.3 Million PCs


Final year, the favored machine cleanup instrument CCleaner suffered a huge present-chain malware assault of all times, whereby hackers compromised the corporate’s servers for extra than a month and replaced the customary version of the instrument with the malicious one.

The malware assault contaminated over 2.three million users who downloaded or up-to-the-minute their CCleaner app between August and September last year from the official web pages with the backdoored version of the instrument.

Now, it turns out that the hackers managed to infiltrate the corporate’s network nearly 5 months before they first replaced the official CCleaner build with the backdoored version, printed Avast executive VP and CTO Ondrej Vlcek on the RSA security conference in San Francisco on Tuesday.

6-Months Timeline of CCleaner Provide Chain Attack

Vlcek shared a rapid timeline of the last year’s incident that came out to be the worst nightmare for the corporate, detailing how and when unknown hackers breached Piriform, the corporate that created CCleaner and changed into as soon as received by Avast in July 2017.

March eleven, 2017 (5 AM local time)—Attackers first accessed an unattended workstation of among the CCleaner builders, which changed into as soon as connected to Piriform network, the usage of a ways flung toughen instrument TeamViewer.


The company believes attackers reused the developer’s credentials got from old knowledge breaches to access the TeamViewer narrative and managed to set up malware the usage of VBScript on the third attempt.

March 12, 2017 (four AM local time)—The employ of the first machine, attackers penetrated into the 2nd unattended computer connected to the identical network and opened a backdoor by scheme of Windows RDP (A long way away Desktop Carrier) protocol.

hacking computer

The employ of RDP access, the attackers dropped a binary and a malicious payload—a 2nd stage malware (older version) that changed into as soon as later brought to Forty CCleaner users—on the aim computer’s registry.

March 14, 2017—Attackers contaminated the first computer with the older version of the 2nd stage malware as neatly.

April four, 2017—Attackers compiled a customised version of ShadowPad, an unsuitable backdoor that allows attackers to decide on up further malicious modules or collect knowledge, and this payload the corporate believes changed into as soon as the third stage of the CCleaner assault.

April 12, 2017—About a days later, attackers installed the Third stage payload on four computer programs within the Piriform network (as a mscoree.dll library) and a build server (as a .NET runtime library).

Between mid-April and July—All over this period, the attackers ready the malicious version of CCleaner, and tried to infiltrate totally different computer programs within the interior network by installing a keylogger on already compromised programs to assemble credentials, and logging in with administrative privileges by scheme of RDP.

July 18, 2017—Security company Avast received Piriform, the UK-essentially based fully instrument pattern company within the lend a hand of CCleaner with extra than 2 billion downloads.

August 2, 2017—Attackers replaced the customary version of CCleaner instrument from its official web pages with their backdoored version of CCleaner, which changed into as soon as dispensed to thousands and thousands of users.

September thirteen, 2017—Researchers at Cisco Talos detected the malicious version of the instrument, which changed into as soon as being dispensed by scheme of the corporate’s official web pages for extra than a month, and notified Avast at as soon as.

The malicious version of CCleaner had a multi-stage malware payload designed to assemble knowledge from contaminated computer programs and send it lend a hand to an attacker-managed uncover-and-maintain watch over server.

Even supposing Avast, with the abet of the FBI, changed into as soon as ready to shut down the attackers’ uncover-and-maintain watch over server internal three days of being notified of the incident, the malicious CCleaner instrument had already been downloaded by 2.27 million users.

Moreover, it changed into as soon as found that the attackers had been then ready to set up a 2nd-stage payload on Forty selected computer programs operated by predominant international technology companies, including Google, Microsoft, Cisco, Intel, Samsung, Sony, HTC, Linksys, D-Link, Akamai and VMware.

Nonetheless, the corporate has no proofs if the third stage payload with ShadowPad changed into as soon as dispensed to any of those targets.

“Our investigation printed that ShadowPad had been beforehand mature in South Korea, and in Russia, the build attackers intruded a computer, observing a cash switch.” Avast stated.

“The oldest malicious executable mature within the Russian assault changed into as soon as inbuilt 2014, which implies the crew within the lend a hand of it would possibly maybe had been spying for years.”

Per their diagnosis of the ShadowPad executable from the Piriform network, Avast believes that the malicious attackers within the lend a hand of the malware had been active for a truly lengthy time, spying on establishments and organizations so totally.