Malicious PDF — malware analysis report

Static analysis result for SHA-256 81d74747778df7c0…

MALICIOUS

PDF

9.3 KB
MD5: 384048f46766858e1b37f4dd0f473752 SHA-1: b27e45e855942f34ac37a937eaf83ff984bf0b45 SHA-256: 81d74747778df7c0ff0836ba8f6854e122dd0e5a3e6bbf1905101d0ff1656de0
266 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link T1027 Obfuscated Files or Information

This PDF exploits CVE-2007-5659 using a combination of PDF JavaScript actions and obfuscated JavaScript streams. The critical heuristic 'CVE_2007_5659: Collab.collectEmailInfo' indicates the specific vulnerability targeted. The embedded JavaScript, particularly the 'annotation_subject_callee_hex_stage_000.js' and 'legacy_pdfkit_stage_001.js' files, is heavily obfuscated using `eval()` and `unescape()` calls, suggesting it's designed to download and execute a second-stage payload. The ClamAV detection further confirms its malicious nature.

Heuristics 9

  • 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)
  • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
7218a1c68060953321573daa035b16f5f32928ce25a9eb656690dbe78cd9464e
pdf-javascript-stream PDF /JS object 7 at offset 0x19B 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
dc0416b2faf55ef5ef4f1667b11f155b40435a42a529c777b9bbbe3f460ac8f0
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5269 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
43e233742933e4985aca6aa099645bdd2aa232cc30d7d88420c660f913ff0814
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2B5 12396 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
618be0a004607ec02665f34c6574328635b6f1bac59e83f1685ebca24db74dc2
deobfuscated-js PDF JavaScript deobfuscation pass 67394 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).