Malicious PDF — malware analysis report

Static analysis result for SHA-256 836530c8f8f654db…

MALICIOUS

PDF

12.2 KB
MD5: 9b59ca6ad8606e4b62e3d2a69405cc55 SHA-1: 0db515a5b079b68745295843abf49447d933d59c SHA-256: 836530c8f8f654db2beca34459499e6636ee0f6f16f07ca95ee6177761c77fdf
186 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link

The PDF document contains embedded JavaScript that is obfuscated and designed to be executed as a stager. The critical heuristic 'CVE_2007_5659: Collab.collectEmailInfo' indicates the exploitation of a known vulnerability in PDF readers. The JavaScript is recovered and deobfuscated, suggesting it's intended to download and execute a second-stage payload. The ClamAV detection further confirms the malicious nature of the file.

Heuristics 7

  • 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-36063 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36063
  • 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
eb39e2de4dbbc100de6d3e30aa43ff78fa075618862ba1ebba5151ea3a3b848d
pdf-javascript-stream PDF /JS object 7 at offset 0x19D 273 bytes
annotation_subject_callee_hex_stage_000.js
c98025403521a30abf7fd13be3c636b8f235fcd3da29178dd522e33f9df82bce
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5208 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
76aeb1afeac38332afa49456d8a3f555b4944b53437f2eaae53b4c63443e399d
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2D6 12444 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
233f4c12c9620a75c13a113ea9598059026eed9086f9d083b0050cd4d580cf0b
deobfuscated-js PDF JavaScript deobfuscation pass 73841 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).