Vulnerabilities > CVE-2017-2798 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Marklogic 8.06
Attack vector
NETWORK Attack complexity
MEDIUM Privileges required
NONE Confidentiality impact
PARTIAL Integrity impact
PARTIAL Availability impact
PARTIAL Summary
An exploitable heap corruption vulnerability exists in the GetIndexArray functionality of Antenna House DMC HTMLFilter as used by MarkLogic 8.0-6. A specially crafted XLS file can cause a heap corruption resulting in arbitrary code execution. An attacker can send or provide a malicious XLS file to trigger this vulnerability.
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| Application | 1 |
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Buffer Overflow via Environment Variables This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
- Overflow Buffers Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an attacker. As a consequence, an attacker is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the attackers' choice.
- Client-side Injection-induced Buffer Overflow This type of attack exploits a buffer overflow vulnerability in targeted client software through injection of malicious content from a custom-built hostile service.
- Filter Failure through Buffer Overflow In this attack, the idea is to cause an active filter to fail by causing an oversized transaction. An attacker may try to feed overly long input strings to the program in an attempt to overwhelm the filter (by causing a buffer overflow) and hoping that the filter does not fail securely (i.e. the user input is let into the system unfiltered).
- MIME Conversion An attacker exploits a weakness in the MIME conversion routine to cause a buffer overflow and gain control over the mail server machine. The MIME system is designed to allow various different information formats to be interpreted and sent via e-mail. Attack points exist when data are converted to MIME compatible format and back.
Seebug
| bulletinFamily | exploit |
| description | ### Summary An exploitable heap corruption vulnerability exists in the GetIndexArray functionality of AntennaHouse DMC HTMLFilter as used by MarkLogioc 8.0-6. A specially crafted XLS file can cause a heap corruption resulting in arbitrary code execution. An attacker can send/provide a malicious XLS file to trigger this vulnerability. ### Tested Versions ``` AntennaHouse DMC HTMLFilter shipped with MarkLogic 8.0-6 fb1a22fa08c986ec3614284f4e912b0a /opt/MarkLogic/Converters/cvtofc/libdhf_rdoc.so 15b0acc464fba28335239f722a62037f /opt/MarkLogic/Converters/cvtofc/libdmc_comm.so 1eabb31236c675f9856a7d001b339334 /opt/MarkLogic/Converters/cvtofc/libdhf_rxls.so 1415cbc784f05db0e9db424636df581a /opt/MarkLogic/Converters/cvtofc/libdhf_comm.so 4ae366fbd4540dd4c750e6679eb63dd4 /opt/MarkLogic/Converters/cvtofc/libdmc_conf.so 81db1b55e18a0cb70a78410147f50b9c /opt/MarkLogic/Converters/cvtofc/libdhf_htmlif.so d716dd77c8e9ee88df435e74fad687e6 /opt/MarkLogic/Converters/cvtofc/libdhf_whtml.so e01d37392e2b2cea757a52ddb7873515 /opt/MarkLogic/Converters/cvtofc/convert ``` ### Product URLs https://www.antennahouse.com/antenna1/ ### CVSSv3 Score 8.3 - CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H ### Details This vulnerability is present in the AntennaHouse DMC HTMLFilter which is used, among others, to convert XLS files to (X)HTML form. This product is mainly used by MarkLogic for office document conversions as part of their web based document search and rendering engine. A specially crafted XLS file can lead to heap corruption and can ultimately result in remote code execution. ``` Running the XLS to HTML converter under Valgrind we can see the following result: icewall@ubuntu:~/bugs/cvtofc_86$ valgrind ./convert config_xls/ ==38273== Memcheck, a memory error detector ==38273== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al. ==38273== Using Valgrind-3.10.1 and LibVEX; rerun with -h for copyright info ==38273== Command: ./convert config_xls/ ==38273== input=/home/icewall/bugs/cvtofc_86/config_xls/toconv.xls output=/home/icewall/bugs/cvtofc_86/config_xls/conv.html type=2 info.options='0' Return from GetFileInfo=0 HtmlInfo.GroupName=UTF-8 HtmlInfo.DefLangName=English HtmlInfo.bBigEndian=0 HtmlInfo.options=0 HtmlInfo.SheetId=0 HtmlInfo.SlideId=0 HtmlInfo.lpFunc=(nil) HtmlInfo.szImageFolder= ==38273== Invalid write of size 4 ==38273== at 0x4053B38: GetIndexArray (in /home/icewall/bugs/cvtofc_86/libdhf_rxls.so) ==38273== by 0x405325C: DHF_RGetObject (in /home/icewall/bugs/cvtofc_86/libdhf_rxls.so) ==38273== by 0x403979E: FilterToHtml (in /home/icewall/bugs/cvtofc_86/libdhf_htmlif.so) ==38273== by 0x4038AFB: DHF_GetHtml_V11 (in /home/icewall/bugs/cvtofc_86/libdhf_htmlif.so) ==38273== by 0x8049AF7: main (in /home/icewall/bugs/cvtofc_86/convert) ==38273== Address 0x4c5b474 is 4,820 bytes inside an unallocated block of size 6,248 in arena "client" ``` The out-of-bounds write occurs in the `GetIndexArray` function. Let's check the pseudocode of the `GetIndexArray` function and try to spot the vulnerable code: ``` Line 1 signed int __cdecl GetIndexArray(struct_a1_1 *a1) Line 2 { Line 3 struct_v1 *blankRec; // eax@1 Line 4 int word1_1; // edx@1 Line 5 int _size; // edx@1 Line 6 _DWORD *_buffer; // eax@1 Line 7 int index; // esi@3 Line 8 Line 9 blankRec = (struct_v1 *)(a1->dword7A4 + (a1->dword7B0 << 6) - 64); Line 10 rw_1 = blankRec->rw + 1; Line 11 a1->col_1 = blankRec->col + 1; Line 12 _size = a1->col_1 * rw_1; Line 13 a1->size = _size; Line 14 _buffer = (_DWORD *)DMC_malloc(4 * _size); Line 15 a1->buffer = _buffer; Line 16 if ( !_buffer ) Line 17 return 12; Line 18 memset(a1->buffer, 0xFF, 4 * a1->size); Line 19 for ( index = 0; index < a1->count; ++index ) Line 20 a1->buffer[a1->col_1 * a1->labelSstes[index].cell.rw + (unsigned __int16)a1->labelSstes[index].cell.col] = index; Line 21 return 0; Line 22 } ``` There are plenty of places where integer overflows can occur, however, looking for write operations, we see the `line 20` has the potential to result in an out-of-bounds write. The space for `a1->buffer` is allocated at `line 14`, based on the mulitplication of `blankRec->col` and `blankRec->rw`. The BlankRec in MS-XLS is: ``` 2.4.20 Blank The Blank record specifies an empty cell with no formula (section 2.2.2) or value. ``` And its location in our PoC is 0x13D1: ``` Offset 0 1 2 3 4 5 6 7 8 9 A B C D E F 000013C0 0E 00 06 00 .... 000013D0 1B 00 .. ``` Where the `a1->labelSstes` structure is : ``` 2.4.149 LabelSst The LabelSst record specifies a cell that contains a string. ``` and the location of this structure in the PoC is 0x13BE: ``` Offset 0 1 2 3 4 5 6 7 8 9 A B C D E F 000013B0 0E 00 .. 000013C0 FF FF 80 00 10 00 00 00 ˇˇÄ..... ``` In our case the result of the multiplication of `a1->col_1` (0x08) and `a1->labelSstes[index].cell.rw` (0x0E) and adding `a1->labelSstes[index].cell.col` (0xFF) to it (0x1006fF) is much bigger than allocated space of `a1->buffer` which leads to an arbitrary out-of-bounds write. ### Crash Information ``` Program received signal SIGSEGV, Segmentation fault. [----------------------------------registers-----------------------------------] EAX: 0x810bbb8 --> 0x0 EBX: 0xf7fd1c24 --> 0x1fb2c ECX: 0x810afb0 --> 0x0 EDX: 0x1006f ESI: 0x3c ('<') EDI: 0x8097d10 --> 0x0 EBP: 0xfffec8b8 --> 0xfffec8e8 --> 0xfffec918 --> 0xfffeccf8 --> 0xffffd068 --> 0x0 ESP: 0xfffec8a0 --> 0x6 EIP: 0xf7fcab38 (mov DWORD PTR [eax+edx*4],esi) EFLAGS: 0x10206 (carry PARITY adjust zero sign trap INTERRUPT direction overflow) [-------------------------------------code-------------------------------------] 0xf7fcab29: imul eax,DWORD PTR [edi+0x9ec] 0xf7fcab30: add edx,eax 0xf7fcab32: mov eax,DWORD PTR [edi+0x9f4] => 0xf7fcab38: mov DWORD PTR [eax+edx*4],esi 0xf7fcab3b: inc esi 0xf7fcab3c: cmp esi,DWORD PTR [edi+0x9a4] 0xf7fcab42: jl 0xf7fcab14 0xf7fcab44: mov eax,0x0 [------------------------------------stack-------------------------------------] 0000| 0xfffec8a0 --> 0x6 0004| 0xfffec8a4 --> 0xe 0008| 0xfffec8a8 --> 0x4 0012| 0xfffec8ac --> 0xf7fd1c24 --> 0x1fb2c 0016| 0xfffec8b0 --> 0x0 0020| 0xfffec8b4 --> 0x8097d10 --> 0x0 0024| 0xfffec8b8 --> 0xfffec8e8 --> 0xfffec918 --> 0xfffeccf8 --> 0xffffd068 --> 0x0 0028| 0xfffec8bc --> 0xf7fca25d (mov esi,eax) [------------------------------------------------------------------------------] Legend: code, data, rodata, value Stopped reason: SIGSEGV 0xf7fcab38 in GetIndexArray () from ./libdhf_rxls.so gdb-peda$ bt #0 0xf7fcab38 in GetIndexArray () from ./libdhf_rxls.so #1 0xf7fca25d in DHF_RGetObject () from ./libdhf_rxls.so #2 0xf7fd479f in FilterToHtml () from ./libdhf_htmlif.so #3 0xf7fd3afc in DHF_GetHtml_V11 () from ./libdhf_htmlif.so #4 0x08049af8 in main () #5 0xf7d74af3 in __libc_start_main (main=0x8049730 <main>, argc=0x2, argv=0xffffd104, init=0x8049f70 <__libc_csu_init>, fini=0x8049f60 <__libc_csu_fini>, rtld_fini=0xf7feb160 <_dl_fini>, stack_end=0xffffd0fc) at libc-start.c:287 #6 0x08048ad1 in _start () gdb-peda$ exploitable Description: Access violation on destination operand Short description: DestAv (9/29) Hash: 6f45d697880ae583ed9077b284dc1049.6f45d697880ae583ed9077b284dc1049 Exploitability Classification: EXPLOITABLE Explanation: The target crashed on an access violation at an address matching the destination operand of the instruction. This likely indicates a write access violation, which means the attacker may control the write address and/or value. Other tags: AccessViolation (28/29) ``` ### Timeline * 2017-02-28 - Vendor Disclosure * 2017-05-04 - Public Release ### CREDIT * Discovered by Marcin 'Icewall' Noga of Cisco Talos. |
| id | SSV:96514 |
| last seen | 2017-11-19 |
| modified | 2017-09-18 |
| published | 2017-09-18 |
| reporter | Root |
| title | AntennaHouse DMC HTMLFilter GetIndexArray Code Execution Vulnerability(CVE-2017-2798) |
Talos
| id | TALOS-2017-0291 |
| last seen | 2019-05-29 |
| published | 2017-05-04 |
| reporter | Talos Intelligence |
| source | http://www.talosintelligence.com/vulnerability_reports/TALOS-2017-0291 |
| title | AntennaHouse DMC HTMLFilter GetIndexArray Code Execution Vulnerability |