Live exploits intercepted for CVE-2017-0143

June 23, 2017

The SonicWall threat research team has intercepted a number of live exploit attacks of the CVE-2017-0143 (MS17-010) in the past few weeks. These exploits triggered a vulnerability on Windows SMB service which improperly handles the Trans command. A successful attack could expose the target host's kernel memory and eventually execute arbitrary code.

In general, the exploits send a SMB transaction command, which is used for communicate with mailslots (one-way inter-process communication) and named pipes. And then followed by a TRANS_PEEK_NMPIPE subcommand to trigger the kernel memory disclosure vulnerability.

The attack network flow can be decribed as followed:

  1. A Tree Connect request sends from attacker to the server's IPC$.
  2. After server approved, the attacker requests opening the "lsarpc" file.
  3. The server will respond with the FID of "lsarpc" file.
  4. The attacker binds to the file's interface, sends a large request to trigger the vulnerability. And then a TRANS_PEEK_NMPIPE subcommand.
  5. The vulnerability will be triggered, server responds with the kernel memory contents.

The SonicWall threat research team has developed the following signature to protect our customers from this vulnerability:

  • IPS 12849: Windows SMB Remote Code Execution (MS17-010) 6