Malicious PDF — malware analysis report

Static analysis result for SHA-256 1c8ddfa57d1aa5f0…

MALICIOUS

PDF

12.1 KB
MD5: fb868ebc5c64cfcd6d2c56eef65d153c SHA-1: 244752ac813c052d574bbc28dff0af2b159adde1 SHA-256: 1c8ddfa57d1aa5f03f8f9da820cda06caa5cca9672c0f6b9b1b85bb2a15bee4b
186 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, triggered by the CVE-2007-5659 vulnerability using the 'collab.collectEmailInfo' method. This JavaScript is heavily obfuscated and appears to be a stager, as indicated by the heuristic 'PDF_ANNOT_SUBJECT_CALLEE_HEX_STAGER' and the presence of multiple deobfuscated JavaScript files. The primary function of this stager is likely to download and execute a second-stage payload.

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
18b9558ff6b9f89ad9756b01b55fa42da85e0062f372419ce5981e5c94bd577b
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5228 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
4b914ac73950e96e7dd52423e3062ed9657959002f77e42e7f4fc1e91af50e47
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2D6 12432 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
d3daa861f40316d61d3cb90768f3b60b62219706da4d20a41b0dbbf64b90bdde
deobfuscated-js PDF JavaScript deobfuscation pass 80224 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).