Malicious PDF — malware analysis report

Static analysis result for SHA-256 cfb738aa0d787f98…

MALICIOUS

PDF

36.8 KB
MD5: a769fded8a5362d35efcdba59fd33252 SHA-1: 935b8d2442209a3434ca99c14fe32a5c0cb240aa SHA-256: cfb738aa0d787f9872b1f9b1a020b2864a981603218876316534731634ea0ad9
306 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious File T1059.001 Command and Scripting Interpreter: JavaScript T1059.007 Command and Scripting Interpreter: JavaScript

The PDF file contains embedded JavaScript that is obfuscated using `unescape()` and `eval()` calls, indicating malicious intent. The critical heuristic `CVE_2007_5659` specifically points to the use of `Collab.collectEmailInfo` for exploitation, a known vulnerability in older Adobe Reader versions. The presence of U3D content further suggests an exploit attempt. The primary attack vector involves leveraging a JavaScript stager to execute malicious code, likely for further payload delivery or system compromise.

Heuristics 10

  • Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659
    PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
  • U3D/3D content in PDF — Adobe Reader 3D parser CVE-family indicator high CVE related PDF_U3D_CVE_RELATED
    PDF contains U3D (Universal 3D) or 3D annotation content — CVE-2011-2462 and CVE-2009-3953 are critical vulnerabilities in Adobe Reader's U3D processing that allow arbitrary code execution. U3D content in PDFs is extremely rare in normal documents.
  • ClamAV: Pdf.Exploit.Agent-35912 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35912
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • Annotation subject callee-key hex JavaScript stager high PDF_ANNOT_SUBJECT_CALLEE_HEX_STAGER
    PDF JavaScript uses syncAnnotScan()/getAnnots() to read an indirect annotation /Subject stream, percent-decodes it through marker replacement, then uses a callee.toString()-derived key to decode and eval the final exploit stage.
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed stream)
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
7218a1c68060953321573daa035b16f5f32928ce25a9eb656690dbe78cd9464e
pdf-javascript-stream PDF /JS object 7 at offset 0x1A2 201 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
annotation_subject_callee_hex_stage_000.js
d4697c3d2b298c5f1dd241acfac269704bc99274227688b2c57405faade09a66
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x151 5412 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
14ea3d4024ae426bc85ac1fee2f79e7d9af805d77b1defc6c1a8e4d204a1689b
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2BC 12729 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
581ad6e1dcc082f4eb622c75b8fb60f328f6ad6974cfe65b1e6b91db2d4a5388
deobfuscated-js PDF JavaScript deobfuscation pass 202408 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
u3d_00_off00002717.bin
70cf2aead4823e6d2651c9281eed0aa967449da358f439efb9e8e707421175e0
pdf-3d-stream PDF U3D 3D stream at offset 0x2717 28021 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.79, consistent with packed or encrypted content.