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Updated with Valve’s response: Valve, in a statement on August 22, said that its HackerOne bug bounty program, should not have turned away Kravets when he reported the second vulnerability and called it “a mistake”.

A Russian security researcher, Vasily Kravets, has found a second zero-day vulnerability in the Steam gaming platform, in a span of two weeks. The researcher said he reported the first Steam zero-day vulnerability earlier in August, to its parent company, Valve, and tried to have it fixed before public disclosure. However, “he said he couldn’t do the same with the second because the company banned him from submitting further bug reports via its public bug bounty program on the HackerOne platform,” ZDNet reports.

Source: amonitoring.ru


This first flaw was a “privilege-escalation vulnerability that can allow an attacker to level up and run any program with the highest possible rights on any Windows computer with Steam installed. It was released after Valve said it wouldn’t fix it (Valve then published a patch, that the same researcher said can be bypassed),” according to Threatpost.

Although Kravets was banned from the Hacker One platform, he disclosed the second flaw that enables a local privilege escalation in the Steam client on Tuesday and said that the flaw would be simple for any OS user to exploit. Kravets told Threatpost that he is not aware of a patch for the vulnerability.

“Any user on a PC could do all actions from exploit’s description (even ‘Guest’ I think, but I didn’t check this). So [the] only requirement is Steam,” Kravets told Threatpost. He also said, “It’s sad and simple — Valve keeps failing. The last patch, that should have solved the problem, can be easily bypassed so the vulnerability still exists. Yes, I’ve checked, it works like a charm.”

Another security researcher, Matt Nelson also said he had found the exact same bug as Kravets had, which “he too reported to Valve’s HackerOne program, only to go through a similar bad experience as Kravets,” ZDNet reports. He said both Valve and HackerOne took five days to acknowledge the bug and later refused to patch it. Further, they locked the bug report when Nelson wanted to disclose the bug publicly and warn users.

“Nelson later released proof-of-concept code for the first Steam zero-day, and also criticized Valve and HackerOne for their abysmal handling of his bug report”, ZDNet reports.

“Despite any application itself could be harmful, achieving maximum privileges can lead to much more disastrous consequences. For example, disabling firewall and antivirus, rootkit installation, concealing of process-miner, theft any PC user’s private data — is just a small portion of what could be done,”  said Kravets.

Kravets demonstrated the second Steam zero-day and also detailed the vulnerability on his website.

Per Threatpost as of August 21, “Valve did not respond to a request for comment about the vulnerability, bug bounty incident and whether a patch is available. HackerOne did not have a comment.”

Other researchers who have participated in Valve’s bug bounty program are infuriated over Valve’s decision to not only block Kravets from submitting further bug reports, but also refusing to patch the flaw.

A user on Reddit writes, “If management isn’t going to take these issues seriously and respect a bug bounty program, then you need to bring about some change from within. Now they are just getting bug reports for free.”

Nelson said the Hacker One “representative said the vulnerability was out of scope to qualify for Valve’s bug bounty program,” Ars Technica writes.

Further, when Nelson said that he was not seeking any monetary gains and only wanted the public to be aware of the vulnerability, the HackerOne representative asked Nelson to “please familiarize yourself with our disclosure guidelines and ensure that you’re not putting the company or yourself at risk. https://www.hackerone.com/disclosure-guidelines.”

Nelson also reported the vulnerability directly to Valve. Valve, first acknowledged the report and “noted that I shouldn’t expect any further communication.” He never heard anything more from the company.

In am email to Ars Technica, Nelson writes, “I can certainly believe that the scoping was misinterpreted by HackerOne staff during the triage efforts. It is mind-blowing to me that the people at HackerOne who are responsible for triaging vulnerability reports for a company as large as Valve didn’t see the importance of Local Privilege Escalation and simply wrote the entire report off due to misreading the scope.”

A HackerOne spokeswoman told Ars Technica, “We aim to explicitly communicate our policies and values in all cases and here we could have done better. Vulnerability disclosure is an inherently murky process and we are, and have always been, committed to protecting the interests of hackers. Our disclosure guidelines emphasize mutual respect and empathy, encouraging all to act in good faith and for the benefit of the common good.”

Katie Moussouris, founder and CEO of Luta Security, also said, “Silencing the researcher on one issue is in complete violation of the ISO standard practices, and banning them from reporting further issues is simply irresponsible to affected users who would otherwise have benefited from these researchers continuing to engage and report issues privately to get them fixed. The norms of vulnerability disclosure are being warped by platforms that put profits before people.”

Valve agrees that turning down Kravets’ request was “a mistake”

Valve, in a statement on August 22, said that its HackerOne bug bounty program, should not have turned away Kravets when he reported the second vulnerability and called it a mistake. In an email statement to ZDNet, a Valve representative said that “the company has shipped fixes for the Steam client, updated its bug bounty program rules, and is reviewing the researcher’s ban on its public bug bounty program.”

The company also writes, “Our HackerOne program rules were intended only to exclude reports of Steam being instructed to launch previously installed malware on a user’s machine as that local user. Instead, misinterpretation of the rules also led to the exclusion of a more serious attack that also performed local privilege escalation through Steam. 

In regards to the specific researchers, we are reviewing the details of each situation to determine the appropriate actions. We aren’t going to discuss the details of each situation or the status of their accounts at this time.”

To know more about this news in detail, read Kravets’ blog post. You could also check out Threatpost’s detailed coverage.

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