| Severity |
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| Remote |
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| Type |
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| Description |
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A local privilege escalation vulnerability has been found in the Linux kernel. |
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Chaitin Security Research Lab discovered that xfrm_replay_verify_len(), as called by xfrm_new_ae(), did not verify that the user-specified replay_window was within the replay state buffer. This allowed for out-of-bounds reads and writes of kernel memory. Chaitin Security showed that this can lead to local privilege escalation by using user namespaces in order to configure XFRM. |
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XFRM configuration requires CAP_NET_ADMIN so this issue is mitigated in kernels which do not enable user namespaces by default. |
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| References |
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http://www.openwall.com/lists/oss-security/2017/03/29/2 |
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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=677e806da4d916052585301785d847c3b3e6186a |
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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f843ee6dd019bcece3e74e76ad9df0155655d0df |
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| Notes |
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This is the local privilege escalation used against Ubuntu during the 2017 pwn2own contest. |
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