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Very interesting writeup, bookmarked! I wish there was a community willing to reverse engineer those very cheap DVR/NVR video surveillance boxes and boards sold

Very interesting writeup, bookmarked! I wish there was a community willing to reverse engineer those very cheap DVR/NVR video surveillance boxes and boards sold on Ebay and Aliexpress. They have USB, SATA, some GPIOs and quite fast ADC chips on board to achieve high definition video sampling so they could be repurposed for various uses like SDR. They already run Linux inside, although it is predictably tight closed, not updated security-wise and often phones home to Chinese servers, so reverse engineering them would be worth beyond mere hacking. Here's one of these boards, just search for "ahd dvr board". https://www.aliexpress.us/item/3256804455950963.html https://www.aliexpress.us/item/3256804455950963.html

detrites 4y ago
Do you happen to know other spec's on these or similar? (Eg, CPU type/speed, RAM etc)
- squarefoot 4y ago
  Not much info unfortunately. Some of them apparently use a HiSilicon (owned by Huawei) chipset; the following Alibaba page lists some of them among others. https://www.alibaba.com/countrysearch/CN/dvr-motherboard.html https://www.alibaba.com/countrysearch/CN/dvr-motherboard.htm... Here are a few pages I found that could turn out interesting: https://securitycamcenter.com/firmware-chinese-dvr-nvr-security-cameras-h264-h265/ https://securitycamcenter.com/firmware-chinese-dvr-nvr-secur... https://github.com/hisilicon https://github.com/hisilicon And as widely reported, they're quite vulnerable. https://github.com/tothi/pwn-hisilicon-dvr https://github.com/tothi/pwn-hisilicon-dvr https://www.exploit-db.com/exploits/44004 https://www.exploit-db.com/exploits/44004 I wonder if those vulnerabilities could be used to gain root access to the hardware in order to either patch it and make decent security devices, or repurpose them completely, as the hardware is interesting and dirt cheap.
  - detrites 4y ago
    Most interesting, thank you. These may have an ARM Cortex A7 dual-core at 1.3Ghz according to this datasheet for the HiSilicon hi3520dv400 (the 4 channel version): http://wangxunic.com/wp-content/uploads/2019/05/Hi3520DV400.pdf http://wangxunic.com/wp-content/uploads/2019/05/Hi3520DV400.... Not bad at all. And with DDR3.

detrites 4y ago

Do you happen to know other spec's on these or similar? (Eg, CPU type/speed, RAM etc)

squarefoot 4y ago
Not much info unfortunately. Some of them apparently use a HiSilicon (owned by Huawei) chipset; the following Alibaba page lists some of them among others. https://www.alibaba.com/countrysearch/CN/dvr-motherboard.html https://www.alibaba.com/countrysearch/CN/dvr-motherboard.htm... Here are a few pages I found that could turn out interesting: https://securitycamcenter.com/firmware-chinese-dvr-nvr-security-cameras-h264-h265/ https://securitycamcenter.com/firmware-chinese-dvr-nvr-secur... https://github.com/hisilicon https://github.com/hisilicon And as widely reported, they're quite vulnerable. https://github.com/tothi/pwn-hisilicon-dvr https://github.com/tothi/pwn-hisilicon-dvr https://www.exploit-db.com/exploits/44004 https://www.exploit-db.com/exploits/44004 I wonder if those vulnerabilities could be used to gain root access to the hardware in order to either patch it and make decent security devices, or repurpose them completely, as the hardware is interesting and dirt cheap.
- detrites 4y ago
  Most interesting, thank you. These may have an ARM Cortex A7 dual-core at 1.3Ghz according to this datasheet for the HiSilicon hi3520dv400 (the 4 channel version): http://wangxunic.com/wp-content/uploads/2019/05/Hi3520DV400.pdf http://wangxunic.com/wp-content/uploads/2019/05/Hi3520DV400.... Not bad at all. And with DDR3.