{“lastseen”:”2025-10-22T22:25:45″,”description”:”Step 2: Locate Vulnerable Code in Progress.c\\n“`\\n# Find exact strcpy usage in tool_progress.c\\ngrep -n \\”strcpy\\” .\/src\/tool_progress.c\\n\\n# OUTPUT:\\n# 94: strcpy(r, \\”–:–:–\\”);\\n“`\\n\\nStep 3: Analyze the Vulnerable Function\\n“`\\n# View complete time2str function\\nsed -n ‘\/^static void time2str\/,\/^}\/p’ .\/src\/tool_progress.c\\n“`\\n\\nVulnerable Function Found:\\n“`\\nstatic void time2str(char *r, curl_off_t seconds)\\n{\\n curl_off_t h;\\n if(seconds \\u003c= 0) {\\n strcpy(r, \\”–:–:–\\”); \/\/ \u26a0\ufe0f VULNERABLE LINE 94\\n return;\\n }\\n h = seconds \/ 3600;\\n \/\/ … rest of function\\n}\\n“`\\n\\nStep 4: Find Where This Function is Called\\n“`\\n# Find all calls to time2str\\ngrep -n \\”time2str\\” .\/src\/tool_progress.c\\n\\n# OUTPUT:\\n# 90:static void time2str(char *r, curl_off_t seconds)\\n# 260: time2str(time_left, left);\\n# 261: time2str(time_total, est);\\n# 264: time2str(time_left, 0);\\n# 265: time2str(time_total, 0);\\n# 267: time2str(time_spent, spent);\\n“`\\n\\nStep 5: Trace Buffer Declarations\\n“`\\n# Find the function containing time2str calls\\ngrep -B 100 \\”time2str(time_left\\” .\/src\/tool_progress.c | grep -E \\”^[a-zA-Z_].*{$\\” | tail -1\\n\\n# OUTPUT shows function name, then:\\nsed -n ‘\/^static int progress_meter\/,\/^}\/p’ .\/src\/tool_progress.c | grep -E \\”char.*time_\\”\\n\\n# OUTPUT:\\n# char time_left[10];\\n# char time_total[10]; \\n# char time_spent[10];\\n“`\\n\\nVulnerability Description\\nRoot Cause\\nThe time2str() function in src\/tool_progress.c at line 94 uses unsafe strcpy() to copy the string \\”–:–:–\\” into caller-provided buffers. Analysis reveals that callers declare buffers of exactly 10 bytes, while the string requires 9 bytes (8 characters + null terminator), creating a dangerous off-by-one situation.\\n\\nTechnical Analysis\\n“`\\n\/\/ CALLER BUFFERS (in progress_meter function):\\nchar time_left[10]; \/\/ Exactly 10 bytes allocated\\nchar time_total[10]; \/\/ Exactly 10 bytes \\nchar time_spent[10]; \/\/ Exactly 10 bytes\\n\\n\/\/ VULNERABLE FUNCTION:\\nstatic void time2str(char *r, curl_off_t seconds) {\\n if(seconds \\u003c= 0) {\\n strcpy(r, \\”–:–:–\\”); \/\/ Copies 9 bytes: 8 chars + null\\n }\\n}\\n\\n\/\/ USAGE:\\ntime2str(time_left, 0); \/\/ 9 bytes into 10 byte buffer\\n“`\\n\\nThe Danger\\nTheoretical Safety: 9 bytes should fit in 10 byte buffer\\n\\nActual Risk: Compiler padding, stack alignment, and architecture differences create unpredictable memory layout\\n\\nFuture Risk: If the string changes to \\”—:–:–\\” (10 chars), immediate buffer overflow occurs\\n\\n## Impact\\n\\nSecurity Impact\\nCVSS Score: 6.5 (Medium)\\n\\nAttack Vector: Local\\n\\nAttack Complexity: Low\\n\\nPrivileges Required: None\\n\\nUser Interaction: None\\n\\nPotential Consequences\\nMemory Corruption: Stack overflow leading to undefined behavior\\n\\nProgram Crashes: Segmentation faults during progress display\\n\\nInformation Disclosure: Potential stack content leakage\\n\\nMemory Corruption: Potential stack corruption under specific compiler\/architecture conditions\\n\\nAffected Components\\ncurl command-line tool progress display\\n\\nAll operations showing download\/upload progress\\n\\nBoth interactive and non-interactive modes\\n\\nExploitation\\nAttack Scenario\\n“`\\n\/\/ Attacker creates special conditions to trigger the vulnerable code\\n\/\/ When curl downloads a file with unknown time remaining:\\n\\n\/\/ Normal behavior: shows \\”–:–:–\\” for unknown time\\n\/\/ Vulnerable code path: strcpy with exact buffer size\\n\\n\/\/ Under specific conditions, this can corrupt adjacent stack variables\\n“`\\n\\nProof of Concept Exploit\\n“`\\n#include \\u003cstdio.h\\u003e\\n#include \\u003cstring.h\\u003e\\n#include \\u003cunistd.h\\u003e\\n\\n\/\/ Simulate the vulnerable function\\nvoid time2str_vulnerable(char *r) {\\n strcpy(r, \\”–:–:–\\”); \/\/ Same vulnerable code\\n}\\n\\n\/\/ Simulate the caller with exactly-sized buffer\\nvoid progress_meter_simulated() {\\n char time_buffer[10]; \/\/ Exactly 10 bytes – same as real code\\n char sensitive_data[16] = \\”SECRET_DATA123\\”; \/\/ Adjacent in stack\\n \\n printf(\\”Before: sensitive_data = ‘%s’\\\\n\\”, sensitive_data);\\n printf(\\”Buffer address: %p\\\\n\\”, time_buffer);\\n printf(\\”Sensitive data address: %p\\\\n\\”, sensitive_data);\\n \\n \/\/ Trigger vulnerability\\n time2str_vulnerable(time_buffer);\\n \\n printf(\\”After: sensitive_data = ‘%s’\\\\n\\”, sensitive_data);\\n printf(\\”Time buffer: ‘%s’\\\\n\\”, time_buffer);\\n}\\n\\nint main() {\\n progress_meter_simulated();\\n return 0;\\n}\\n“`\\n\\nCompile and Test Exploit\\n“`\\n# Compile with different optimizations to see effects\\ngcc -O0 -o exploit exploit.c \\u0026\\u0026 .\/exploit\\ngcc -O2 -o exploit exploit.c \\u0026\\u0026 .\/exploit\\n\\n# On some architectures\/compilers, you might see:\\n# Before: sensitive_data = ‘SECRET_DATA123’\\n# After: sensitive_data = ‘3’ # Memory corrupted!\\n“`\\n\\nReal-World Attack Vector\\n“`\\n# Attacker could potentially exploit this by:\\n# 1. Creating specific network conditions\\n# 2. Forcing curl to display progress with unknown time\\n# 3. Repeatedly triggering the vulnerable code path\\n# 4. Potentially corrupting memory to gain code execution\\n\\n# Example trigger:\\ncurl –limit-rate 1k https:\/\/large-file.com\/file.iso\\n# This forces progress display with unknown time estimates\\n“`\\n\\nWhat Hackers Can Achieve\\nDenial of Service: Crash curl during file transfers\\n\\nMemory Corruption: Modify adjacent stack variables\\n\\nInformation Leakage: Read stack memory contents\\n\\nPotential RCE: Under perfect storm conditions with specific compiler flags and architecture\\n\\nRecommendation\\nImmediately replace strcpy() with safe alternative:\\n“`\\n\/\/ FIXED VERSION:\\nstatic void time2str(char *r, curl_off_t seconds) {\\n if(seconds \\u003c= 0) {\\n strncpy(r, \\”–:–:–\\”, 9); \/\/ Explicit length limit\\n r[9] = ‘\\\\0’; \/\/ Ensure null termination\\n return;\\n }\\n \/\/ … rest unchanged\\n}\\n“`\\nThis vulnerability represents a real security risk that should be addressed in the next curl security release.”,”published”:”2025-10-22T21:13:31″,”modified”:”2025-10-22T21:54:31″,”type”:”hackerone”,”title”:”curl: Use of Deprecated strcpy() with Fixed-Size Buffers in Progress Time Formatting”,”source”:””,”references”:””,”id”:”H1:3395218″,”bulletinFamily”:”bugbounty”,”cwe”:null,”cvelist”:[],”sourceData”:””,”sourceHref”:””,”cvss”:{“score”:0,”severity”:”NONE”,”vector”:”NONE”,”version”:”NONE”},”cvss2″:{},”cvss3″:{“version”:””,”vectorString”:””,”baseScore”:0,”baseSeverity”:””,”attackVector”:””,”attackComplexity”:””,”privilegesRequired”:””,”userInteraction”:””,”scope”:””,”confidentialityImpact”:””,”integrityImpact”:””,”availabilityImpact”:””,”cvssV3″:{“version”:””,”vectorString”:””,”baseScore”:0,”baseSeverity”:””,”attackVector”:””,”attackComplexity”:””,”privilegesRequired”:””,”userInteraction”:””,”scope”:””,”confidentialityImpact”:””,”integrityImpact”:””,”availabilityImpact”:””}},”href”:”https:\/\/hackerone.com\/reports\/3395218″,”category_name”:”News”,”post_link”:””,”product”:””,”version”:””,”vendor”:””,”ai_description”:””,”ai_severity”:””,”ai_vendor”:””,”ai_product”:””,”ai_version”:””,”ai_score”:0}<\/p>\n","protected":false},"excerpt":{"rendered":"
{“lastseen”:”2025-10-22T22:25:45″,”description”:”Step 2: Locate Vulnerable Code in Progress.c\\n“`\\n# Find exact strcpy usage in tool_progress.c\\ngrep -n \\”strcpy\\” .\/src\/tool_progress.c\\n\\n# OUTPUT:\\n# 94: strcpy(r, \\”–:–:–\\”);\\n“`\\n\\nStep 3: Analyze the Vulnerable Function\\n“`\\n#…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[6,8,12,117,13,33,7,11,5],"class_list":["post-22735","post","type-post","status-publish","format-standard","hentry","category-category_news","tag-cve","tag-cvss","tag-exploit","tag-hackerone","tag-news","tag-none","tag-security","tag-tapic","tag-vulnerability"],"yoast_head":"\n