Cisco DPC3939 Firmware

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) devices allows remote attackers to execute arbitrary commands as root by leveraging local network access and connecting to the syseventd server, as demonstrated by copying configuration data into a readable filesystem.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) devices allows remote attackers to obtain root access to the Network Processor (NP) Linux system by enabling a TELNET daemon (through CVE-2017-9479 exploitation) and then establishing a TELNET session.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) devices allows Network Processor (NP) Linux users to obtain root access to the Application Processor (AP) Linux system via shell metacharacters in commands.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421733-160420a-CMCST); Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST); Cisco DPC3939B (firmware version dpc3939b-v303r204217-150321a-CMCST); Cisco DPC3941T (firmware version DPC3941_2.5s3_PROD_sey); and Arris TG1682G (eMTA&DOCSIS version 10.0.132.SIP.PC20.CT, software version TG1682_2.2p7s2_PROD_sey) devices allows remote attackers to execute arbitrary code via a specific (but unstated) exposed service. NOTE: the scope of this CVE does NOT include the concept of "Unnecessary Services" in general; the scope is only a single service that is unnecessarily exposed, leading to remote code execution. The details of that service might be disclosed at a later date.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) and DPC3941T (firmware version DPC3941_2.5s3_PROD_sey) devices allows remote attackers to access the web UI by establishing a session to the wan0 WAN IPv6 address and then entering unspecified hardcoded credentials. This wan0 interface cannot be accessed from the public Internet.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421733-160420a-CMCST); Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST); Cisco DPC3939B (firmware version dpc3939b-v303r204217-150321a-CMCST); Cisco DPC3941T (firmware version DPC3941_2.5s3_PROD_sey); and Arris TG1682G (eMTA&DOCSIS version 10.0.132.SIP.PC20.CT, software version TG1682_2.2p7s2_PROD_sey) devices does not include the HTTPOnly flag in a Set-Cookie header for administration applications, which makes it easier for remote attackers to obtain potentially sensitive information via script access to cookies.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421733-160420a-CMCST) and DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) devices sets the CM MAC address to a value with a two-byte offset from the MTA/VoIP MAC address, which indirectly allows remote attackers to discover hidden Home Security Wi-Fi networks by leveraging the embedding of the MTA/VoIP MAC address into the DNS hostname.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421733-160420a-CMCST) and DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) devices allows remote attackers to discover a CM MAC address by sniffing Wi-Fi traffic and performing simple arithmetic calculations.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) devices allows remote attackers to compute password-of-the-day values via unspecified vectors.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) devices allows remote attackers to obtain unintended access to the Network Processor (NP) 169.254/16 IP network by adding a routing-table entry that specifies the LAN IP address as the router for that network.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) devices allows remote attackers to write arbitrary data to a known /var/tmp/sess_* pathname by leveraging the device's operation in UI dev mode.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421733-160420a-CMCST); Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST); and Arris TG1682G (eMTA&DOCSIS version 10.0.132.SIP.PC20.CT, software version TG1682_2.2p7s2_PROD_sey) devices makes it easy for remote attackers to determine the hidden SSID and passphrase for a Home Security Wi-Fi network.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421733-160420a-CMCST) and DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) devices allows remote attackers to discover the CM MAC address by connecting to the device's xfinitywifi hotspot.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) and DPC3941T (firmware version DPC3941_2.5s3_PROD_sey) devices allows remote attackers to discover a WAN IPv6 IP address by leveraging knowledge of the CM MAC address.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) devices allows local users (e.g., users who have command access as a consequence of CVE-2017-9479 exploitation) to read arbitrary files via UPnP access to /var/IGD/.

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421733-160420a-CMCST); Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST); Cisco DPC3939B (firmware version dpc3939b-v303r204217-150321a-CMCST); Cisco DPC3941T (firmware version DPC3941_2.5s3_PROD_sey); and Arris TG1682G (eMTA&DOCSIS version 10.0.132.SIP.PC20.CT, software version TG1682_2.2p7s2_PROD_sey) devices does not set the secure flag for cookies in an https session to an administration application, which makes it easier for remote attackers to capture these cookies by intercepting their transmission within an http session.