Malicious PDF — malware analysis report

Static analysis result for SHA-256 18ceaa9f2407c337…

MALICIOUS

PDF

9.4 KB
MD5: 2a973802443d1942ab9abfad44965c4e SHA-1: 06618cb7983123f08f453ca37d490abf89ddc31c SHA-256: 18ceaa9f2407c3371c3750e3460c0914ec0d094c3604ce1957e1d116ce1d9811
278 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains JavaScript that exploits CVE-2007-5659 using the syncAnnotScan primitive. This script is designed to download a second-stage payload from the URL http://google.analytics.com.zelhnalbivd.info/kav/KAV3%20.asp/eH16db03d3V0100f080006Ra81eac5b102T2fe71a2e201l000aK9d81846c. The ML classifier also strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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)
  • Adobe Reader APSB08-13 patch-range version gate (CVE-2007-5659) high CVE likely PDF_JS_ADOBE_APSB08_13_PATCH_GATE
    PDF JavaScript gates the exploit payload on (>= 8 && < 8.1.1) OR (< 7.1) — the Reader 7.0.x / 8.0–8.1.1 window patched by Adobe APSB08-13 for the CVE-2007-5659 Collab.collectEmailInfo buffer overflow. Only kits that target that exact bug check both of those patch points; benign scripts do not.
  • Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY
    Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
  • 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.
  • PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL
    Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://google.analytics.com.zelhnalbivd.info/kav/KAV3%20.asp/eH16db03d3V0100f080006Ra81eac5b102T2fe71a2e201l000aK9d81846c

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
9f17df95bc71874fe0f2dcb9f0e8f529cdb3604910d27079f2fbde52cabda2a8
pdf-javascript-stream PDF /JS object 7 at offset 0x19B 256 bytes
generic_stage_recovery_000.js
6c29f58cd24a1c109c3171cedc5243aa6196e7e1029a40931b7f7192717d4139
deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 7 at offset 0x19B 246 bytes
annotation_subject_callee_hex_stage_000.js
b1c9fcd58a2db863e9156d257e0b330d0c41f4ec77beed2bfee60451bf6b9943
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5137 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
f9856576eab9c63b483a5cf6e31e745518434db110f5d188f046b2328edaffb5
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2D0 12100 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
663d70eb0c48d2e12531a83df9dea4888157bfbefd8306e4117d8adfa320bfce
deobfuscated-js PDF JavaScript deobfuscation pass 43589 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).