Malicious PDF — malware analysis report

Static analysis result for SHA-256 d858efb33628e8d1…

MALICIOUS

PDF

37.2 KB
MD5: 1efa0d521a66ae165051d4c65d9307ce SHA-1: 1f139a1ca66f1af8eebc92d07eac905ca2bc552b SHA-256: d858efb33628e8d1b99f51ab884183c33852e9fa427967abec9745c4e600eaaf
306 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious File T1059.001 Command and Scripting Interpreter: JavaScript T1027 Obfuscated Files or Information T1190 Exploit Public-Facing Application

The PDF file contains embedded JavaScript that is heavily obfuscated using `unescape()` and `eval()` calls. The critical heuristic `CVE_2007_5659` specifically points to the use of `collab.collectEmailInfo` and a hex decoder, indicating a known exploit for Adobe Reader. The script's primary function appears to be decoding and executing a malicious payload, likely for further exploitation or malware delivery. The presence of multiple deobfuscated JavaScript files and a U3D stream further supports the exploit vector.

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
badf9966d918d172dd5df638564c1f22b939f4d78c7b5533f86587cd953db03c
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x151 5671 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
77c35b0da2ed82ae72932f7788fa13332a32e9c5a1a9b25ba5af692ab67895f1
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2BC 13195 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
c8e5133a52d209aae8dd698f82a48fb5453df33fe5d59862835357849bbafe79
deobfuscated-js PDF JavaScript deobfuscation pass 204226 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_off000028d1.bin
70cf2aead4823e6d2651c9281eed0aa967449da358f439efb9e8e707421175e0
pdf-3d-stream PDF U3D 3D stream at offset 0x28D1 28021 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.79, consistent with packed or encrypted content.